dev-libs/boost: fix build on macOS / Apple Silicon

This commits fix three problems in existing Boost 1.82.0 ebuilds,
allowing one to install Boost on macOS, including Apple Silicon.

1. Boost wants to build static library, which is unsupported on macOS.

Using the unmodified ebuild, Boost fails because the build system
wants to pass the "-static" flag to ar, but this option (and static
linking in general) is unsupported by macOS, creating this error
message:

    arm64-apple-darwin22-ar: only one of -a and -[bi] options allowed

It turned out that "toolset=darwin" is actually broken in Boost [1] and
has even been removed from Boost since 2019 [2]. Thus, the fix is to
remove the option compiler="darwin".

2. error: O_LARGEFILE was not declared in this scope

It appears that on modern macOS, 64-bit file I/O is already the default,
and there's no special support for options like O_LARGEFILE. Thus, on
on Darwin, we avoid running the command append-lfs-flags.

3. invalid install_name found, your application or library will crash at runtime

To fix the broken install_name and references, a hack is used on Darwin
to find a list paths. The original command began with "grep ^libboost"
to match a library name at the beginning of the output of "otool -XL".
But for some reason, the library names now include a path prefix, such
as:

    bin.v2/libs/thread/build/gcc-12.1/gentoorelease/pch-off/
    threadapi-pthread/threading-multi/visibility-hidden/
    libboost_thread.dylib

Thus, matching at the beginning of the line no longer works. To fix
the problem, we instead use "grep libboost" to allow lines with a
path prefix to be matched as well. We then extract the basename the
filename from the path.

[1] https://web.archive.org/web/20160713132921/https://svn.boost.org/trac/boost/ticket/9772#comment:19
[2] https://github.com/boostorg/build/issues/528

Closes: https://github.com/gentoo/gentoo/pull/30758
Closes: https://bugs.gentoo.org/904983
Signed-off-by: Yifeng Li <tomli@tomli.me>
Signed-off-by: David Seifert <soap@gentoo.org>

1 files changed, 23 insertions, 13 deletions

diff --git a/dev-libs/boost/boost-1.82.0.ebuild b/dev-libs/boost/boost-1.82.0.ebuild
index efe85c331913..30ce182a1f86 100644
--- a/dev-libs/boost/boost-1.82.0.ebuild
+++ b/dev-libs/boost/boost-1.82.0.ebuild
@@ -16,7 +16,7 @@ S="${WORKDIR}/${PN}_${MY_PV}"
 
 LICENSE="Boost-1.0"
 SLOT="0/${PV}" # ${PV} instead of the major version due to bug 486122
-KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris ~x86-winnt"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris ~x86-winnt"
 IUSE="bzip2 context debug doc icu lzma +nls mpi numpy python tools zlib zstd"
 REQUIRED_USE="python? ( ${PYTHON_REQUIRED_USE} )"
 # the tests will never fail because these are not intended as sanity
@@ -71,13 +71,8 @@ create_user-config.jam() {
 	fi
 
 	local compiler compiler_version compiler_executable="$(tc-getCXX)"
-	if [[ ${CHOST} == *-darwin* ]]; then
-		compiler="darwin"
-		compiler_version="$(gcc-fullversion)"
-	else
-		compiler="gcc"
-		compiler_version="$(gcc-version)"
-	fi
+	compiler="gcc"
+	compiler_version="$(gcc-version)"
 
 	if use mpi; then
 		local mpi_configuration="using mpi ;"
@@ -194,8 +189,15 @@ src_configure() {
 	# Use C++17 globally as of 1.80
 	append-cxxflags -std=c++17
 
-	# need to enable LFS explicitly for 64-bit offsets on 32-bit hosts (#894564)
-	append-lfs-flags
+	if [[ ${CHOST} != *-darwin* ]]; then
+		# On modern macOS, file I/O is already 64-bit by default,
+		# there's no support for special options like O_LARGEFILE.
+		# Thus, LFS must be disabled.
+		#
+		# On other systems, we need to enable LFS explicitly for 64-bit
+		# offsets on 32-bit hosts (#894564)
+		append-lfs-flags
+	fi
 }
 
 multilib_src_compile() {
@@ -242,16 +244,24 @@ multilib_src_install() {
 				install_name_tool -id "/${d#${D}}" "${d}"
 				eend $?
 				# fix references to other libs
+				# these paths look like this:
+				# bin.v2/libs/thread/build/gcc-12.1/gentoorelease/pch-off/
+				#  threadapi-pthread/threading-multi/visibility-hidden/
+				#  libboost_thread.dylib
 				refs=$(otool -XL "${d}" | \
 					sed -e '1d' -e 's/^\t//' | \
-					grep "^libboost_" | \
+					grep "libboost_" | \
 					cut -f1 -d' ')
 				local r
 				for r in ${refs}; do
-					ebegin "    correcting reference to ${r}"
+					# strip path prefix from references, so we obtain
+					# something like libboost_thread.dylib.
+					local r_basename=${r##*/}
+
+					ebegin "    correcting reference to ${r_basename}"
 					install_name_tool -change \
 						"${r}" \
-						"${EPREFIX}/usr/lib/${r}" \
+						"${EPREFIX}/usr/lib/${r_basename}" \
 						"${d}"
 					eend $?
 				done