gcc: drop explicit -fno-PIE, let gcc figure this out.

Explicit -fno-PIE results in parts of libstdc++.a being built non-PIC,
which breaks -static-libstdc++ for PIE binaries.
Also requires lots of fiddling in the build system which we try to
avoid.

See #8842.

srcpkgs/gcc/template

@@ -3,7 +3,7 @@ _majorver=7.2
 
 pkgname=gcc
 version=${_majorver}.0
-revision=3
+revision=4
 short_desc="The GNU C Compiler"
 maintainer="Juan RP <xtraeme@voidlinux.eu>"
 homepage="http://gcc.gnu.org"
@@ -80,21 +80,6 @@ replaces="gcc-c++>=0"
 pre_configure() {
 	# _FORTIFY_SOURCE needs an optimization level.
 	sed -i "/ac_cpp=/s/\$CPPFLAGS/\$CPPFLAGS -O2/" {gcc,libiberty}/configure
-
-	if [ -n "$nopie" ]; then
-		# Fix configure failures by adding -no-pie when linking conftest.c/.cpp files
-		find -name configure -exec sed -i {} \
-			-e 's;$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS;& -no-pie;' \
-			-e 's;$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS;& -no-pie;' \
-			\;
-		# Fix linking error for fixincl by adding -no-pie
-		sed -i fixincludes/Makefile.in \
-			-e 's;-o $(FI);-no-pie &;' \
-			-e 's;-o $@;-no-pie &;'
-		# Fix linking error for gotools by adding -no-pie
-		sed -i gotools/Makefile.in \
-			-e 's;LINK = .*;& -no-pie;'
-	fi
 }
 do_configure() {
 	local _langs _args _hash
@@ -167,6 +152,10 @@ do_configure() {
 	export CFLAGS="${CFLAGS/-D_FORTIFY_SOURCE=2/}"
 	export CXXFLAGS="${CXXFLAGS/-D_FORTIFY_SOURCE=2/}"
 
+	# Disable explicit -fno-PIE, gcc will figure this out itself.
+	export CFLAGS="${CFLAGS//-fno-PIE/}"
+	export CXXFLAGS="${CXXFLAGS//-fno-PIE/}"
+
 	_args+=" --prefix=/usr"
 	_args+=" --mandir=/usr/share/man"
 	_args+=" --infodir=/usr/share/info"