scons and ccache

This is an attempt to use ccache with scons. I'd really like to have
something like this to avoid waiting 30/40 minutes for Godot to build.

part of the issue is that scons executes the compiler in a clear
environment for some reasons and thus we loose CCACHE_DIR, ccache then
tries to write to $HOME/.ccache and so we can't just unsed NO_CCACHE
from scons.port.mk and enjoy the speed-up.

However, scons uses the compiler we want, so if we tweak the compiler
wrapper to inject CCACHE_DIR we win!

This allows to pass from:
2244.08 real 7359.21 user 644.35 sys
to
213.30 real 147.20 user 162.25 sys

when building games/godot with a warm cache. it's really nice :)

To be fair, scons has its own caching mechanism built-in[0] but I don't
think we can use it as we would need to patch the SConscript files to
add CacheDir (well, we have to patch 'em anyway almost always in the
end, but i don't think it'd be a good idea to add this too.)

[0]: https://scons.org/doc/production/HTML/scons-user.html#chap-caching

There are also other things that we may consider in the future to speed
up scons builds a little bit more. The recent-ish support for building
with ninja is interesting for example, with that over ccache I can build
godot with a warm cache in 197s, but it's still marked as experimental.

Thoughts?

Index: infrastructure/mk/bsd.port.mk
===================================================================
RCS file: /home/cvs/ports/infrastructure/mk/bsd.port.mk,v
retrieving revision 1.1573
diff -u -p -r1.1573 bsd.port.mk
--- infrastructure/mk/bsd.port.mk 19 May 2022 13:12:40 -0000 1.1573
+++ infrastructure/mk/bsd.port.mk 28 Jun 2022 10:13:18 -0000
@@ -447,7 +447,7 @@ CCACHE_ENV ?=
CCACHE_DIR ?= ${WRKOBJDIR_${PKGPATH}}/.ccache
MAKE_ENV += CCACHE_DIR=${CCACHE_DIR} ${CCACHE_ENV}
CONFIGURE_ENV += CCACHE_DIR=${CCACHE_DIR}
-COMPILER_WRAPPER += ccache
+COMPILER_WRAPPER += env CCACHE_DIR=${CCACHE_DIR} ccache
. if !exists(${LOCALBASE}/bin/ccache)
ERRORS += "Fatal: USE_CCACHE is set, but ccache is not installed."
. endif
Index: devel/scons/scons.port.mk
===================================================================
RCS file: /home/cvs/ports/devel/scons/scons.port.mk,v
retrieving revision 1.11
diff -u -p -r1.11 scons.port.mk
--- devel/scons/scons.port.mk 7 Jun 2022 11:38:09 -0000 1.11
+++ devel/scons/scons.port.mk 28 Jun 2022 10:13:44 -0000
@@ -20,7 +20,6 @@ MODSCONS_ENV?= CC="${CC}" \

MODSCONS_FLAGS?=
ALL_TARGET?=
-NO_CCACHE?=Yes

MODSCONS_BUILD_TARGET = \
${SETENV} ${MAKE_ENV} ${MODSCONS_BIN} -C ${WRKSRC} \