如何处理丢失的libgcc_s.a

Question

使用外部工具链别名code sourcery lite 2011交叉编译使用buildroot的库，从而导致

output/host/opt/ext-toolchain/bin/../lib/gcc/arm-none-linux-gnueabi/4.6.1/../../../../arm-none-linux-gnueabi/bin/ld: cannot find -lgcc_s
collect2: ld returned 1 exit status

因为一个明显缺失的libgcc_s.a

# find . -iname "libgcc*"        
./output/host/usr/arm-buildroot-linux-gnueabi/sysroot/lib/libgcc_s.so
./output/host/usr/arm-buildroot-linux-gnueabi/sysroot/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/armv4t/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/armv4t/lib/libgcc_s.so
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/thumb2/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/thumb2/lib/libgcc_s.so
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/lib/libgcc_s.so.1
./output/host/opt/ext-toolchain/arm-none-linux-gnueabi/libc/lib/libgcc_s.so
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/armv4t/libgcc.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/armv4t/libgcc_eh.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/plugin/libgcc
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/thumb2/libgcc.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/thumb2/libgcc_eh.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/libgcc.a
./output/host/opt/ext-toolchain/lib/gcc/arm-none-linux-gnueabi/4.6.1/libgcc_eh.a

有没有办法避开这个问题，但仍然是静态链接？是否有CLFAGS或LDFLAGS选项可以静态地链接除libgcc_s**?**以外的所有内容？

到目前为止，尝试过的内容(除了阅读ld和gcc手册页的适用部分之外)：

CFLAGS="-static -static-libgcc"
CFLAGS="-static -shared-libgcc"
CFLAGS="-static -static-libgcc -Wl,-Bstatic"
CFLAGS="-static -shared-libgcc -Wl,-Bstatic"

在添加-Wl,-lgcc_s,-Bstatic之后，我得到了大量未定义/未知的符号.(ld表示，-Bshared不是有效的选项)

/home/bernhard/buildroot-2013.08/output/target/usr/lib/libgio-2.0.a(libgio_2_0_la-glocalfileinfo.o): In function `_g_local_file_info_get':
glocalfileinfo.c:(.text+0x2d90): warning: Using 'getgrgid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libgio-2.0.a(libgio_2_0_la-glocalvfs.o): In function `g_local_vfs_parse_name':
glocalvfs.c:(.text+0x174): warning: Using 'getpwnam' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libglib-2.0.a(libglib_2_0_la-gutils.o): In function `g_get_user_database_entry':
gutils.c:(.text+0x254): warning: Using 'getpwuid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0x24c): warning: Using 'setpwent' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0x25c): warning: Using 'endpwent' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0xa0): warning: Using 'getpwnam_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
gutils.c:(.text+0xe0): warning: Using 'getpwuid_r' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libgio-2.0.a(libgio_2_0_la-gnetworkaddress.o): In function `g_network_address_parse_sockaddr':
gnetworkaddress.c:(.text+0x1ac): warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
<<<< SNIP >>>>
/home/bernhard/buildroot-2013.08/output/target/usr/lib/libxml2.a(xmlschemastypes.o): In function `xmlSchemaGetCanonValue':
xmlschemastypes.c:(.text+0x7680): undefined reference to `trunc'
xmlschemastypes.c:(.text+0x76bc): undefined reference to `trunc'
xmlschemastypes.c:(.text+0x7710): undefined reference to `floor'
xmlschemastypes.c:(.text+0x7760): undefined reference to `floor'
collect2: ld returned 1 exit status

Answer 1

也许可以消除使用libgcc_s.a的标志，这些标志可以阻止gcc使用内部内置函数(比如内置的memcpy)，但最好的方法是定位和使用它。

看起来这个选项应该可以防止内置-fno-builtin的使用。有关更多细节，请参见这里：http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html

与共享libgcc_s.so的链接

如果缺少libgcc_s.a，或者希望使用具有其他静态可执行文件的共享libgcc_s，则应该完成以下工作：

CFLAGS="-static -Wl,-Bdynamic,-lgcc_s,-Bstatic"