Which gcc version introduced `-fstack-protector-strong`? - bash

Question

In my build script, I want to conditionally add -fstack-protector-strong to my CFLAGS if the gcc supports it (my project builds using multiple versions of gcc).
I want my build script (written in bash) to parse the output of gcc --version and automatically add this flag if the gcc supports it.
Which version of gcc is the earliest to include the -fstack-protector-strong flag?

Answer 1

I want my build script (written in bash) to parse the output of gcc --version and automatically add this flag if the gcc supports it.
Instead of doing that, just call gcc -fstack-protector-strong with a valid source file and see if it compiles. Such method works universally for any compile option, which will save you time for searching which version has which options. You may take inspiration from CMake check_c_compile_flag function.

Answer 2

Taking inspiration from #KamilCuk's answer but bashifying it:
add_supported_cc_flag() {
CC=$1
CFLAG_TO_CHECK=$2
C_FILE=/tmp/test.$$.c
O_FILE=${C_FILE/.c/.o}
rm -f ${C_FILE}
cat > ${C_FILE} <<EOF
int main() { return 0; }
EOF
if $CC ${CFLAG_TO_CHECK} -c ${C_FILE} -o ${O_FILE} >/dev/null 2>&1
then
echo ${CFLAG_TO_CHECK}
fi
rm -f ${C_FILE} ${O_FILE}
}
CFLAGS="${CFLAGS} $(add_supported_cc_flag gcc -fstack-protector-strong)"

Answer 3

It appears that -fstack-protector-strong was first available in gcc 4.9.0.
The option doesn't show up in https://gcc.gnu.org/onlinedocs/gcc-4.8.5/gcc/Optimize-Options.html (4.8.5 was the last 4.8.x gcc version), but the option does show up in https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Optimize-Options.html.
Note that -fstack-protector-all and -fstack-protector are available prior to gcc 4.9.0.