gcc: Introduce a knob to configure gcc to default to PIE

GCCPIE flag which is empty by default adds "--enable-default-pie"
configure option for harderned distros

We do not require to add -fpie -pie flag externally anymore

(From OE-Core rev: 1c7e195c94764d680a12a49b870f04cd58860f81)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gcc/gcc-configure-common.inc

@@ -22,6 +22,8 @@ EXTRA_OECONF_INITIAL ?= ""
 GCCMULTILIB ?= "--disable-multilib"
 GCCTHREADS ?= "posix"
 
+GCCPIE ??= ""
+
 EXTRA_OECONF = "\
     ${@['--enable-clocale=generic', ''][d.getVar('USE_NLS') != 'no']} \
     --with-gnu-ld \
@@ -29,6 +31,7 @@ EXTRA_OECONF = "\
     --enable-languages=${LANGUAGES} \
     --enable-threads=${GCCTHREADS} \
     ${GCCMULTILIB} \
+    ${GCCPIE} \
     --enable-c99 \
     --enable-long-long \
     --enable-symvers=gnu \