Convert binary wrapper to a symlink wrapper.v2.0

Before the change:
   /usr/bin/gcc and friends were a copy of /usr/$(libexecdir)/misc/gcc-config
After the change:
   /usr/bin/gcc is a symlink to a real compiler binary. Examples:
       /usr/${CTARGET}/gcc-bin/${GCC_VER}/gcc (native)
       /usr/${CHOST}/${CTARGET}/gcc-bin/${GCC_VER}/gcc (cross)

gcc-config is a binary wrapper that does (or did) a few things:

- [removed in 2011] injects additional CFLAGS_${ABI}

  Removed in commit 7ac40f3eb8434961f70485247d883f5b3009dcf2
  "Stop auto appending CFLAGS_<abi> from the env."

- traverses PATH for real compiler binary and reexecutes it.

- reads /etc/env.d/05gcc-${CTARGET} as a fallback if PATH is empty.

Today binary wrapper does only PATH resolution and re-execution.

This change has a few minor benefits:

- PATH will not contain explicit /usr/${CHOST}/${CTARGET}/gcc-bin/${GCC_VER}
  entry. This will make PATH shorter for those who have mavy cross-compilers
  installed.

- compiler switch will not require sourcing '. /etc/profile' as changes are
  applied as soon an symlink is switched.

- ccache will see gcc binary changes directly and react accordingly.
  Previously in default configuration ccache cache depended on state of
  /usr/$(libexecdir)/misc/gcc-config

  See bug #640958 where ccache did not notice USE=-pie -> USE=pie switch.

- Reasoning about PATH ordering is straightforward: all available binaries
  (as symlinks) are in /usr/bin.

  See bug #255695 where PATH ordering changed and bug #626606 where
  people get confused on what is in /usr/bin/gcc binary.

Bug: https://bugs.gentoo.org/626606
Bug: https://bugs.gentoo.org/255695
Bug: https://bugs.gentoo.org/640958
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

3 files changed, 3 insertions, 3 deletions

diff --git a/tests/rw-multi-native-configs/test.select b/tests/rw-multi-native-configs/test.select
index c6d9daf..a9cc1d1 100644
--- a/tests/rw-multi-native-configs/test.select
+++ b/tests/rw-multi-native-configs/test.select
@@ -18,10 +18,10 @@ for (( i = 1; i < 4; ++i )) ; do
 	esac
 
 	for b in "${do_want[@]}" ; do
-		[[ -e usr/bin/${b} ]] || exit 1
+		[[ -L usr/bin/${b} ]] || exit 1
 	done
 	for b in "${dont_want[@]}" ; do
-		[[ -e usr/bin/${b} ]] && exit 1
+		[[ -L usr/bin/${b} ]] && exit 1
 	done
 	[[ -e etc/env.d/04gcc-${CHOST} ]] || exit 1
 done
diff --git a/tests/rw-multi-native-configs/usr/lib/gcc-config/wrapper b/tests/rw-multi-native-configs/usr/lib/gcc-config/wrapper
deleted file mode 100755
index e69de29..0000000
--- a/tests/rw-multi-native-configs/usr/lib/gcc-config/wrapper
+++ /dev/null
diff --git a/tests/source/test.whitespace b/tests/source/test.whitespace
index 28108ae..26d1bdb 100644
--- a/tests/source/test.whitespace
+++ b/tests/source/test.whitespace
@@ -1,2 +1,2 @@
 #!/bin/bash
-! egrep -nH '[[:space:]]+$' "${TROOT}"/../{gcc-config,wrapper.c}
+! egrep -nH '[[:space:]]+$' "${TROOT}"/../gcc-config