Added ability to bootstrap ghc on systems with gmp-5

To understand why it is supposed to work, please, read comments in dev-lang/ghc/files/ghc-apply-gmp-hack
Package-Manager: portage-2.1.8.3/cvs/Linux x86_64

1 files changed, 61 insertions, 0 deletions

diff --git a/dev-lang/ghc/files/ghc-apply-gmp-hack b/dev-lang/ghc/files/ghc-apply-gmp-hack
new file mode 100644
index 000000000000..a0b4ab8ffd9c
--- /dev/null
+++ b/dev-lang/ghc/files/ghc-apply-gmp-hack
@@ -0,0 +1,61 @@
+# this script is expected to be sourced by ghc ebuilds built against libgmp.so.3 library
+#
+# > source "${FILESDIR}/ghc-apply-gmp-hack"
+#
+# What it does and why it works:
+#  > GMP 5.0 is upwardly source and binary compatible with 4.x, and 3.x versions,
+#  > except for applications that use the semi-documented mpn_bdivmod  function.
+#
+#  > The solib numbers now reflect the removal of the documented but preliminary
+#  > mpn_bdivmod function; we correctly flag incompatibility with GMP 4.3.
+#  > GMP 5.0.0 has this wrong, and should perhaps be uninstalled to avoid confusion.
+#
+# taken from http://gmplib.org/gmp5.0.html
+#
+# Luckily, ghc does not use the 'mpn_bdivmod' function, so we can easily use
+# libgmp.so.10 for binaries which require libgmp.so.3
+#
+# So, this script checks whether this system has libgmp.so.10 and if has
+# shows it to bootstrapper-compiler via populating LD_LIBRARY_PATH
+# (it actually exports function doing this)
+#
+# After bootstrapping resulting compiler will not depend on old libgmp
+# Newer ghc binaries must be built against newer gmp
+#
+# Blames should be directed to Sergei Trofimovich <slyfox@gentoo.org>
+
+# should be used:
+# > inherit multilib
+# > ...
+# > # somewhere in src_unpack() { # as early as possible, right after unpacking source/binary
+# > source "${FILESDIR}/ghc-apply-gmp-hack" "$(get_libdir)"
+
+local libdir_name=$1
+# let's see if we are in affected system
+if has_version '>=dev-libs/gmp-5.0.1'; then
+	local libgmpso3=$ROOT/usr/$libdir_name/libgmp.so.3
+	local libgmpso10=$ROOT/usr/$libdir_name/libgmp.so.10
+
+	# bother user only if things won't work for him
+	if [[ ! -e "$libgmpso3" ]]; then
+		if use binary; then
+			eerror "You have requested precompiled binary installation, which is"
+			eerror "built against 'libgmp.so.3'. You can create compatibility symlink"
+			eerror "if you have '$libgmpso10' and wish to use installed binary:"
+			eerror " # ln -s libgmp.so.10 '$libgmpso3'"
+			die "libgmp.so.3 not found"
+		else
+			if [[ -e "$libgmpso10" ]]; then
+				local fake_solib_dir=${S}/fake_solibs
+				mkdir "$fake_solib_dir" || die "failed to make fake lib dir"
+				elog "Enabling libgmp hack:"
+				elog "| Making symlink: '$fake_solib_dir/libgmp.so.3' -> '$libgmpso10'"
+				ln -s "$libgmpso10" "$fake_solib_dir/libgmp.so.3" || die "failed to make fake symlink"
+				export LD_LIBRARY_PATH=$fake_solib_dir${LD_LIBRARY_PATH:+:}$LD_LIBRARY_PATH
+				elog "| setting new LD_LIBRARY_PATH='$LD_LIBRARY_PATH'"
+			else
+				eerror "'$libgmpso3' and '$libgmpso10' are not found. Please, report the breakage."
+			fi
+		fi
+	fi
+fi