root@LEDE:~# gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/lto-wrapper
Target: mipsel-openwrt-linux-gnu
Configured with: /home/ryzhovau/Entware/build_dir/target-mipsel_mips32r2_glibc-2.27/gcc-6.3.0/configure --target=mipsel-openwrt-linux --host=mipsel-openwrt-linux --build=x86_64-pc-linux-gnu --program-prefix= --program-suffix= --prefix=/opt --exec-prefix=/opt --bindir=/opt/bin --sbindir=/opt/sbin --libexecdir=/opt/lib --sysconfdir=/opt/etc --datadir=/opt/share --localstatedir=/opt/var --mandir=/opt/man --infodir=/opt/info --disable-nls --build=x86_64-pc-linux-gnu --host=mipsel-openwrt-linux-gnu --target=mipsel-openwrt-linux-gnu --enable-languages=c,c++ --with-bugurl=https://dev.openwrt.org/ --with-pkgversion='OpenWrt GCC 6.3.0' --enable-shared --enable-__cxa_atexit --with-default-libstdcxx-abi=gcc4-compatible --enable-target-optspace --with-gnu-ld --with-stage1-ldflags='-Wl,-rpath=/opt/lib -Wl,--dynamic-linker=/opt/lib/ld.so.1' --with-specs='-Wl,-rpath=/opt/lib -Wl,--dynamic-linker=/opt/lib/ld.so.1' --with-boot-ldflags='static-libstdc++ -static-libgcc -Wl,-rpath=/opt/lib -Wl,--dynamic-linker=/opt/lib/ld.so.1' --disable-nls --disable-libsanitizer --disable-libvtv --disable-libcilkrts --disable-libmudflap --disable-multilib --disable-libgomp --disable-libquadmath --disable-libssp --disable-decimal-float --disable-libstdcxx-pch --with-host-libstdcxx=-lstdc++ --prefix=/opt --libexecdir=/opt/lib --with-local-prefix=/opt --with-float=soft --with-default-libstdcxx-abi=gcc4-compatible
Thread model: posix
gcc version 6.3.0 (OpenWrt GCC 6.3.0)
COMPILER_PATH=/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/:/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/:/opt/lib/gcc/mipsel-openwrt-linux-gnu/:/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/:/opt/lib/gcc/mipsel-openwrt-linux-gnu/
LIBRARY_PATH=/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/:/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-msoft-float' '-mllsc' '-mno-shared' '-EL' '-mabi=32'
 /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/collect2 -plugin /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/liblto_plugin.so -plugin-opt=/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/lto-wrapper -plugin-opt=-fresolution=/opt/tmp/cc8BWJXT.res -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc_s --eh-frame-hdr -EL -dynamic-linker /lib/ld.so.1 -melf32ltsmip /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crt1.o /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crti.o /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crtbegin.o -L/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0 -L/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/../../.. -rpath=/opt/lib --dynamic-linker=/opt/lib/ld.so.1 -lgcc_s -lc -lgcc_s /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crtend.o /opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crtn.o
/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crt1.o: In function `__start':
(.text+0xc): undefined reference to `main'
/opt/lib/gcc/mipsel-openwrt-linux-gnu/6.3.0/crt1.o: In function `__start':
(.text+0x10): undefined reference to `main'
collect2: error: ld returned 1 exit status