diff --git a/cmake/freebsd_aarch64_toolchain_clang.cmake b/cmake/freebsd_aarch64_toolchain_clang.cmake
new file mode 100644
index 0000000..d626299
--- /dev/null
+++ b/cmake/freebsd_aarch64_toolchain_clang.cmake
@@ -0,0 +1,7 @@
+set(CMAKE_CROSSCOMPILING TRUE)
+
+set(CMAKE_SYSTEM_NAME FreeBSD)
+set(CMAKE_SYSTEM_PROCESSOR aarch64)
+
+set(CMAKE_C_COMPILER clang)
+set(CMAKE_CXX_COMPILER clang++)
diff --git a/cmake/freebsd_x86_64_toolchain_clang.cmake b/cmake/freebsd_x86_64_toolchain_clang.cmake
new file mode 100644
index 0000000..29e03ad
--- /dev/null
+++ b/cmake/freebsd_x86_64_toolchain_clang.cmake
@@ -0,0 +1,7 @@
+set(CMAKE_CROSSCOMPILING TRUE)
+
+set(CMAKE_SYSTEM_NAME FreeBSD)
+set(CMAKE_SYSTEM_PROCESSOR x86_64)
+
+set(CMAKE_C_COMPILER clang)
+set(CMAKE_CXX_COMPILER clang++)
diff --git a/release_scripts/build_all.sh b/release_scripts/build_all.sh
index a897ac3..d5ca00e 100755
--- a/release_scripts/build_all.sh
+++ b/release_scripts/build_all.sh
@@ -20,6 +20,8 @@ fi
 rm -f p2pool.tar
 tar -f p2pool.tar -c ../cmake -c ../external -c ../src -c ../CMakeLists.txt -c ../LICENSE -c ../README.md
 
+ln p2pool.tar freebsd_aarch64/p2pool.tar
+ln p2pool.tar freebsd_x64/p2pool.tar
 ln p2pool.tar linux_aarch64/p2pool.tar
 ln p2pool.tar linux_riscv64/p2pool.tar
 ln p2pool.tar linux_x64/p2pool.tar
@@ -27,6 +29,8 @@ ln p2pool.tar windows_x64/p2pool.tar
 ln p2pool.tar macos_aarch64/p2pool.tar
 ln p2pool.tar macos_x64/p2pool.tar
 
+gnome-terminal --tab -- freebsd_aarch64/build.sh $1
+gnome-terminal --tab -- freebsd_x64/build.sh $1
 gnome-terminal --tab -- linux_aarch64/build.sh $1
 gnome-terminal --tab -- linux_riscv64/build.sh $1
 gnome-terminal --tab -- linux_x64/build.sh $1
diff --git a/release_scripts/freebsd_aarch64/Dockerfile b/release_scripts/freebsd_aarch64/Dockerfile
new file mode 100644
index 0000000..d8feff3
--- /dev/null
+++ b/release_scripts/freebsd_aarch64/Dockerfile
@@ -0,0 +1,4 @@
+FROM p2pool_build_ubuntu
+ARG P2POOL_VERSION BUILD_TIMESTAMP
+ADD p2pool.tar p2pool_freebsd_aarch64.sh /p2pool/
+RUN /p2pool/p2pool_freebsd_aarch64.sh p2pool-${P2POOL_VERSION}-freebsd-aarch64 ${BUILD_TIMESTAMP}
diff --git a/release_scripts/freebsd_aarch64/build.sh b/release_scripts/freebsd_aarch64/build.sh
new file mode 100755
index 0000000..09de92a
--- /dev/null
+++ b/release_scripts/freebsd_aarch64/build.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+# Example usage: ./build.sh v4.8.1
+
+cd "$(dirname "$0")"
+[ ! -f "p2pool.tar" ] && tar -f p2pool.tar -c ../../cmake -c ../../external -c ../../src -c ../../CMakeLists.txt -c ../../LICENSE -c ../../README.md
+
+docker build --build-arg P2POOL_VERSION=$1 --build-arg BUILD_TIMESTAMP="$(git show --no-patch --format=%ct $1)" -t p2pool_freebsd_aarch64_build .
+
+docker create --name p2pool_freebsd_aarch64_build_container p2pool_freebsd_aarch64_build:latest
+docker cp p2pool_freebsd_aarch64_build_container:/p2pool/build/p2pool-$1-freebsd-aarch64.tar.gz ../p2pool-$1-freebsd-aarch64.tar.gz
+docker rm p2pool_freebsd_aarch64_build_container
+
+docker image rm -f p2pool_freebsd_aarch64_build
+
+rm p2pool.tar
diff --git a/release_scripts/freebsd_aarch64/p2pool_freebsd_aarch64.sh b/release_scripts/freebsd_aarch64/p2pool_freebsd_aarch64.sh
new file mode 100755
index 0000000..7d159de
--- /dev/null
+++ b/release_scripts/freebsd_aarch64/p2pool_freebsd_aarch64.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+set -e
+
+export TZ=UTC0
+
+CURRENT_DATE=$(date -u -d @$2 +"%Y-%m-%d")
+CURRENT_TIME=$(date -u -d @$2 +"%H:%M:%S")
+TOUCH_DATE=$(date -u -d @$2 +"%Y%m%d%H%M.%S")
+
+flags_size="-ffunction-sections -fdata-sections -Wl,-s -Wl,--gc-sections"
+flags_datetime="-D__DATE__=\"\\\"$CURRENT_DATE\\\"\" -D__TIME__=\"\\\"$CURRENT_TIME\\\"\" -Wno-builtin-macro-redefined"
+
+flags_libs="--target=aarch64-unknown-freebsd12.0 --sysroot=/usr/local/cross-freebsd-aarch64 -Os -flto -fuse-ld=lld -w $flags_size $flags_datetime"
+flags_p2pool="--target=aarch64-unknown-freebsd12.0 --sysroot=/usr/local/cross-freebsd-aarch64 -fuse-ld=lld -Wno-unused-command-line-argument $flags_size $flags_datetime"
+
+cd /p2pool/external/src/curl
+cmake . -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../../../cmake/freebsd_aarch64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_libs" -DBUILD_CURL_EXE=OFF -DBUILD_SHARED_LIBS=OFF -DCURL_DISABLE_INSTALL=ON -DCURL_ENABLE_EXPORT_TARGET=OFF -DCURL_DISABLE_HEADERS_API=ON -DCURL_DISABLE_BINDLOCAL=ON -DBUILD_LIBCURL_DOCS=OFF -DBUILD_MISC_DOCS=OFF -DENABLE_CURL_MANUAL=OFF -DCURL_ZLIB=OFF -DCURL_BROTLI=OFF -DCURL_ZSTD=OFF -DCURL_DISABLE_ALTSVC=ON -DCURL_DISABLE_COOKIES=ON -DCURL_DISABLE_DOH=ON -DCURL_DISABLE_GETOPTIONS=ON -DCURL_DISABLE_HSTS=ON -DCURL_DISABLE_LIBCURL_OPTION=ON -DCURL_DISABLE_MIME=ON -DCURL_DISABLE_NETRC=ON -DCURL_DISABLE_NTLM=ON -DCURL_DISABLE_PARSEDATE=ON -DCURL_DISABLE_PROGRESS_METER=ON -DCURL_DISABLE_SHUFFLE_DNS=ON -DCURL_DISABLE_SOCKETPAIR=ON -DCURL_DISABLE_VERBOSE_STRINGS=ON -DCURL_DISABLE_WEBSOCKETS=ON -DHTTP_ONLY=ON -DCURL_ENABLE_SSL=OFF -DUSE_LIBIDN2=OFF -DCURL_USE_LIBPSL=OFF -DCURL_USE_LIBSSH2=OFF -DENABLE_UNIX_SOCKETS=OFF -DBUILD_TESTING=OFF -DUSE_NGHTTP2=OFF -DBUILD_EXAMPLES=OFF -DP2POOL_BORINGSSL=ON -DCURL_DISABLE_SRP=ON -DOPENSSL_INCLUDE_DIR=../grpc/third_party/boringssl-with-bazel/src/include
+make -j$(nproc)
+cd lib && cp -f libcurl.a .libs
+
+cd /p2pool/external/src/libuv
+rm -rf build
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../../../../cmake/freebsd_aarch64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_libs" -DBUILD_TESTING=OFF -DLIBUV_BUILD_SHARED=OFF
+make -j$(nproc)
+
+cd /p2pool/external/src/libzmq
+rm -rf build
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../../../../cmake/freebsd_aarch64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_libs" -DCMAKE_CXX_FLAGS="$flags_libs" -DWITH_LIBSODIUM=OFF -DWITH_LIBBSD=OFF -DBUILD_TESTS=OFF -DWITH_DOCS=OFF -DENABLE_DRAFTS=OFF -DBUILD_SHARED=OFF
+make -j$(nproc)
+
+cd /p2pool
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_POLICY_VERSION_MINIMUM="3.5" -DCMAKE_TOOLCHAIN_FILE=../cmake/freebsd_aarch64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_p2pool" -DCMAKE_CXX_FLAGS="$flags_p2pool" -DOPENSSL_NO_ASM=ON -DSTATIC_BINARY=ON -DARCH_ID=aarch64
+make -j$(nproc) p2pool
+
+mkdir $1
+
+mv p2pool $1
+mv ../LICENSE $1
+mv ../README.md $1
+
+chmod -R 0644 $1
+chmod 0755 $1/p2pool
+
+tar cvf $1.tar --format=pax --pax-option='exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime' --sort=name --owner=0 --group=0 --mtime="$CURRENT_DATE $CURRENT_TIME" $1
+touch -t $TOUCH_DATE $1.tar
+7z a -mx=9 -tgzip -stl $1.tar.gz $1.tar
diff --git a/release_scripts/freebsd_x64/Dockerfile b/release_scripts/freebsd_x64/Dockerfile
new file mode 100644
index 0000000..3ab2644
--- /dev/null
+++ b/release_scripts/freebsd_x64/Dockerfile
@@ -0,0 +1,4 @@
+FROM p2pool_build_ubuntu
+ARG P2POOL_VERSION BUILD_TIMESTAMP
+ADD p2pool.tar p2pool_freebsd_x64.sh /p2pool/
+RUN /p2pool/p2pool_freebsd_x64.sh p2pool-${P2POOL_VERSION}-freebsd-x64 ${BUILD_TIMESTAMP}
diff --git a/release_scripts/freebsd_x64/build.sh b/release_scripts/freebsd_x64/build.sh
new file mode 100755
index 0000000..5cc3068
--- /dev/null
+++ b/release_scripts/freebsd_x64/build.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+# Example usage: ./build.sh v4.8.1
+
+cd "$(dirname "$0")"
+[ ! -f "p2pool.tar" ] && tar -f p2pool.tar -c ../../cmake -c ../../external -c ../../src -c ../../CMakeLists.txt -c ../../LICENSE -c ../../README.md
+
+docker build --build-arg P2POOL_VERSION=$1 --build-arg BUILD_TIMESTAMP="$(git show --no-patch --format=%ct $1)" -t p2pool_freebsd_x64_build .
+
+docker create --name p2pool_freebsd_x64_build_container p2pool_freebsd_x64_build:latest
+docker cp p2pool_freebsd_x64_build_container:/p2pool/build/p2pool-$1-freebsd-x64.tar.gz ../p2pool-$1-freebsd-x64.tar.gz
+docker rm p2pool_freebsd_x64_build_container
+
+docker image rm -f p2pool_freebsd_x64_build
+
+rm p2pool.tar
diff --git a/release_scripts/freebsd_x64/p2pool_freebsd_x64.sh b/release_scripts/freebsd_x64/p2pool_freebsd_x64.sh
new file mode 100755
index 0000000..1d04d96
--- /dev/null
+++ b/release_scripts/freebsd_x64/p2pool_freebsd_x64.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+set -e
+
+export TZ=UTC0
+
+CURRENT_DATE=$(date -u -d @$2 +"%Y-%m-%d")
+CURRENT_TIME=$(date -u -d @$2 +"%H:%M:%S")
+TOUCH_DATE=$(date -u -d @$2 +"%Y%m%d%H%M.%S")
+
+flags_size="-ffunction-sections -fdata-sections -Wl,-s -Wl,--gc-sections"
+flags_datetime="-D__DATE__=\"\\\"$CURRENT_DATE\\\"\" -D__TIME__=\"\\\"$CURRENT_TIME\\\"\" -Wno-builtin-macro-redefined"
+
+flags_libs="--target=x86_64-unknown-freebsd12.0 --sysroot=/usr/local/cross-freebsd-x86_64 -Os -flto -fuse-ld=lld -w $flags_size $flags_datetime"
+flags_p2pool="--target=x86_64-unknown-freebsd12.0 --sysroot=/usr/local/cross-freebsd-x86_64 -fuse-ld=lld -Wno-unused-command-line-argument $flags_size $flags_datetime"
+
+cd /p2pool/external/src/curl
+cmake . -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../../../cmake/freebsd_x86_64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_libs" -DBUILD_CURL_EXE=OFF -DBUILD_SHARED_LIBS=OFF -DCURL_DISABLE_INSTALL=ON -DCURL_ENABLE_EXPORT_TARGET=OFF -DCURL_DISABLE_HEADERS_API=ON -DCURL_DISABLE_BINDLOCAL=ON -DBUILD_LIBCURL_DOCS=OFF -DBUILD_MISC_DOCS=OFF -DENABLE_CURL_MANUAL=OFF -DCURL_ZLIB=OFF -DCURL_BROTLI=OFF -DCURL_ZSTD=OFF -DCURL_DISABLE_ALTSVC=ON -DCURL_DISABLE_COOKIES=ON -DCURL_DISABLE_DOH=ON -DCURL_DISABLE_GETOPTIONS=ON -DCURL_DISABLE_HSTS=ON -DCURL_DISABLE_LIBCURL_OPTION=ON -DCURL_DISABLE_MIME=ON -DCURL_DISABLE_NETRC=ON -DCURL_DISABLE_NTLM=ON -DCURL_DISABLE_PARSEDATE=ON -DCURL_DISABLE_PROGRESS_METER=ON -DCURL_DISABLE_SHUFFLE_DNS=ON -DCURL_DISABLE_SOCKETPAIR=ON -DCURL_DISABLE_VERBOSE_STRINGS=ON -DCURL_DISABLE_WEBSOCKETS=ON -DHTTP_ONLY=ON -DCURL_ENABLE_SSL=OFF -DUSE_LIBIDN2=OFF -DCURL_USE_LIBPSL=OFF -DCURL_USE_LIBSSH2=OFF -DENABLE_UNIX_SOCKETS=OFF -DBUILD_TESTING=OFF -DUSE_NGHTTP2=OFF -DBUILD_EXAMPLES=OFF -DP2POOL_BORINGSSL=ON -DCURL_DISABLE_SRP=ON -DOPENSSL_INCLUDE_DIR=../grpc/third_party/boringssl-with-bazel/src/include
+make -j$(nproc)
+cd lib && cp -f libcurl.a .libs
+
+cd /p2pool/external/src/libuv
+rm -rf build
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../../../../cmake/freebsd_x86_64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_libs" -DBUILD_TESTING=OFF -DLIBUV_BUILD_SHARED=OFF
+make -j$(nproc)
+
+cd /p2pool/external/src/libzmq
+rm -rf build
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=../../../../cmake/freebsd_x86_64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_libs" -DCMAKE_CXX_FLAGS="$flags_libs" -DWITH_LIBSODIUM=OFF -DWITH_LIBBSD=OFF -DBUILD_TESTS=OFF -DWITH_DOCS=OFF -DENABLE_DRAFTS=OFF -DBUILD_SHARED=OFF
+make -j$(nproc)
+
+cd /p2pool
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_POLICY_VERSION_MINIMUM="3.5" -DCMAKE_TOOLCHAIN_FILE=../cmake/freebsd_x86_64_toolchain_clang.cmake -DCMAKE_C_FLAGS="$flags_p2pool" -DCMAKE_CXX_FLAGS="$flags_p2pool" -DOPENSSL_NO_ASM=ON -DSTATIC_BINARY=ON -DARCH_ID=x86_64
+make -j$(nproc) p2pool
+
+mkdir $1
+
+mv p2pool $1
+mv ../LICENSE $1
+mv ../README.md $1
+
+chmod -R 0644 $1
+chmod 0755 $1/p2pool
+
+tar cvf $1.tar --format=pax --pax-option='exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime' --sort=name --owner=0 --group=0 --mtime="$CURRENT_DATE $CURRENT_TIME" $1
+touch -t $TOUCH_DATE $1.tar
+7z a -mx=9 -tgzip -stl $1.tar.gz $1.tar
diff --git a/release_scripts/images/ubuntu/prepare.sh b/release_scripts/images/ubuntu/prepare.sh
index 1b1c5b3..2626ef9 100755
--- a/release_scripts/images/ubuntu/prepare.sh
+++ b/release_scripts/images/ubuntu/prepare.sh
@@ -7,6 +7,7 @@ _7ZIP_VERSION=2409
 BINUTILS_VERSION=2_44
 CLANG_VERSION=20.1.7
 CMAKE_VERSION=4.0.3
+FREEBSD_VERSION=12.4
 GCC_VERSION=15.1.0
 GLIBC_VERSION=2.41
 LINUX_HEADERS_VERSION=6.15.4
@@ -16,6 +17,8 @@ MINGW_VERSION=12.0.0
 
 _7ZIP_SHA256="914c7e20ad5ef8e4d3cf08620ff8894b28fe11b7eb99809d6930870fbe48a281"
 CMAKE_SHA256="585ae9e013107bc8e7c7c9ce872cbdcbdff569e675b07ef57aacfb88c886faac"
+FREEBSD_AARCH64_SHA256="6c401819bfb93e810c9f9aa670a1e4685f924df5e7e0c9c6397dd6c16c954fa2"
+FREEBSD_X86_64_SHA256="581c7edacfd2fca2bdf5791f667402d22fccd8a5e184635e0cac075564d57aa8"
 GLIBC_SHA256="a5a26b22f545d6b7d7b3dd828e11e428f24f4fac43c934fb071b6a7d0828e901"
 HEADERS_SHA256="0eafd627b602f58d73917d00e4fc3196ba18cba67df6995a42aa74744d8efa16"
 MACOSX_SDK_SHA256="c15cf0f3f17d714d1aa5a642da8e118db53d79429eb015771ba816aa7c6c1cbd"
@@ -297,7 +300,7 @@ git clone --depth=1 --branch v$MINGW_VERSION https://git.code.sf.net/p/mingw-w64
 rm -rf mingw-w64-v$MINGW_VERSION/.git
 
 cd mingw-w64-v$MINGW_VERSION/mingw-w64-headers
-CFLAGS='-O2' ./configure --host=x86_64-w64-mingw32 --prefix=/usr/local/x86_64-w64-mingw32
+CFLAGS='-O2' ./configure --host=x86_64-w64-mingw32 --prefix=/usr/local/x86_64-w64-mingw32 --with-default-msvcrt=msvcrt --with-default-win32-winnt=0x0600
 make install
 
 echo "Install GCC for x86_64-w64-mingw32"
@@ -313,12 +316,12 @@ echo "Install mingw-w64 CRT"
 
 # Need to do it two times for some reason - first time without pthreads, or it will fail to link.
 cd /root/mingw-w64-v$MINGW_VERSION
-CFLAGS='-O2' ./configure --host=x86_64-w64-mingw32 --prefix=/usr/local/x86_64-w64-mingw32
+CFLAGS='-O2' ./configure --host=x86_64-w64-mingw32 --prefix=/usr/local/x86_64-w64-mingw32 --with-default-msvcrt=msvcrt --with-default-win32-winnt=0x0600
 make -j$(nproc)
 make -j$(nproc) install
 
 cd /root/mingw-w64-v$MINGW_VERSION
-CFLAGS='-O2' ./configure --host=x86_64-w64-mingw32 --prefix=/usr/local/x86_64-w64-mingw32 --with-libraries=winpthreads
+CFLAGS='-O2' ./configure --host=x86_64-w64-mingw32 --prefix=/usr/local/x86_64-w64-mingw32 --with-default-msvcrt=msvcrt --with-default-win32-winnt=0x0600 --with-libraries=winpthreads
 make -j$(nproc)
 make -j$(nproc) install
 
@@ -373,6 +376,41 @@ cd /root/osxcross
 TARGET_DIR=/usr/local OSX_VERSION_MIN=10.15 UNATTENDED=1 ./build.sh
 ./build_compiler_rt.sh
 
+echo "Install FreeBSD $FREEBSD_VERSION SDK"
+
+cd /usr/local
+
+FREEBSD_FILE=base.txz
+
+mkdir cross-freebsd-x86_64 && mkdir cross-freebsd-aarch64
+curl -L -Z -o cross-freebsd-x86_64/$FREEBSD_FILE -o cross-freebsd-aarch64/$FREEBSD_FILE https://archive.freebsd.org/old-releases/amd64/$FREEBSD_VERSION-RELEASE/$FREEBSD_FILE https://archive.freebsd.org/old-releases/arm64/$FREEBSD_VERSION-RELEASE/$FREEBSD_FILE
+
+cd /usr/local/cross-freebsd-x86_64
+
+FREEBSD_X86_64_FILE_SHA256="$(sha256sum $FREEBSD_FILE | awk '{ print $1 }')"
+
+if [ $FREEBSD_X86_64_FILE_SHA256 != $FREEBSD_X86_64_SHA256 ]; then
+    echo "Error: SHA256 sum does not match for $FREEBSD_FILE - expected $FREEBSD_X86_64_SHA256, got $FREEBSD_X86_64_FILE_SHA256"
+    exit 1
+fi
+
+tar -xf $FREEBSD_FILE ./lib/ ./usr/lib/ ./usr/include/
+rm $FREEBSD_FILE
+#find /usr/local/cross-freebsd-x86_64/usr/lib -xtype l|xargs ls -l|grep ' /lib/'|awk '{print "ln -sf /usr/local/cross-freebsd-x86_64"$11 " " $9}'|/bin/sh
+
+cd /usr/local/cross-freebsd-aarch64
+
+FREEBSD_AARCH64_FILE_SHA256="$(sha256sum $FREEBSD_FILE | awk '{ print $1 }')"
+
+if [ $FREEBSD_AARCH64_FILE_SHA256 != $FREEBSD_AARCH64_SHA256 ]; then
+    echo "Error: SHA256 sum does not match for $FREEBSD_FILE - expected $FREEBSD_AARCH64_SHA256, got $FREEBSD_AARCH64_FILE_SHA256"
+    exit 1
+fi
+
+tar -xf $FREEBSD_FILE ./lib/ ./usr/lib/ ./usr/include/
+rm $FREEBSD_FILE
+#find /usr/local/cross-freebsd-aarch64/usr/lib -xtype l|xargs ls -l|grep ' /lib/'|awk '{print "ln -sf /usr/local/cross-freebsd-aarch64"$11 " " $9}'|/bin/sh
+
 echo "Deleting system glibc files to force our glibc"
 
 rm /usr/lib/x86_64-linux-gnu/crt1.o