xbps-src: move compiler/linker defaults to env/hardening.sh.

The user can still set his/her defaults via etc/conf, and per
package in the templates.

etc/defaults.conf

@@ -23,15 +23,13 @@ XBPS_INSTALL_ARGS="--repository=http://repo.voidlinux.eu/current --repository=ht
 # Native Compilation/Preprocessor flags for C and C++. Additional settings
 # for the target architecture are also declared in common/build-profiles/<arch>.sh.
 #
-XBPS_CFLAGS="-O2 -pipe -fstack-protector-strong -D_FORTIFY_SOURCE=2"
+XBPS_CFLAGS="-O2 -pipe"
 XBPS_CXXFLAGS="${XBPS_CFLAGS}"
 
 # [OPTIONAL]
-# Linker flags passed to the compiler. By default we use --as-needed to
-# avoid linking extra libraries into binaries. See the following link
-# for info: http://www.gentoo.org/proj/en/qa/asneeded.xml
+# Linker flags passed to the compiler.
 #
-XBPS_LDFLAGS="-Wl,--as-needed -Wl,-z,relro"
+#XBPS_LDFLAGS=""
 
 # [REQUIRED]
 # Command to execute to gain root privileges when using the `update-sys`