Issue #19778 has been updated by usa (Usaku NAKAMURA). Backport changed from 3.0: REQUIRED, 3.1: REQUIRED, 3.2: DONE to 3.0: REQUIRED, 3.1: DONE, 3.2: DONE ruby_3_1 8563a144fda2fd130b672541a84d8bad0b6c4cd2 merged revision(s) bcb3247072e6973d0f6b50ca5fed238d5824bd28,fe0225ff4d5af8b1f54009727b39d0d9b821eea3. ---------------------------------------- Bug #19778: mkmf.rb pkg_config() interaction with RbConfig::CONFIG["cflags"] https://bugs.ruby-lang.org/issues/19778#change-104942 * Author: rhenium (Kazuki Yamaguchi) * Status: Closed * Priority: Normal * Assignee: nobu (Nobuyoshi Nakada) * ruby -v: ruby 3.3.0dev (2023-07-21T09:38:29Z master 22f9735587) [x86_64-linux] * Backport: 3.0: REQUIRED, 3.1: DONE, 3.2: DONE ---------------------------------------- (This was first reported at https://github.com/ruby/openssl/issues/650: The extension's build breaks in a strange way if `RbConfig::CONFIG["*flags"]` contains the path of an OpenSSL installation but `pkg-config` returns the path of a different OpenSSL installation) Commit commit:097c3e9cbbf23718371f08c24b2d2297b039f63f ("mkmf.rb: -I flags to $INCFLAGS", Ruby 2.2) changed how mkmf's `pkg_config()` handles the result of the `pkg-config` command. It now stores the `-I` flags in $INCFLAGS and others in $CFLAGS. mkmf generates a Makefile that compiles source files with: $(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) and link the final library with: $(LDSHARED) -o $@ $(OBJS) $(LIBPATH) $(DLDFLAGS) $(LOCAL_LIBS) $(LIBS) This "new" behavior of `pkg_config()` is problematic when `RbConfig::CONFIG["{C,CPP}FLAGS"]` also provide `-I` flags and `RbConfig::CONFIG["LDFLAGS"]` provides the matching `-L` flags -- for example, if Ruby is compiled with `./configure --with-opt-dir=<dir>`. This would end up with compiling sources with [...] -I<from pkg-config> -I<from RbConfig> [...] and then linking with [...] -L<from RbConfig> -L<from pkg-config> [...] This doesn't seem right. I don't know which should come earlier, but the order should be consistent. The commit in question clearly describes the change in the commit message, but it doesn't have a linked issue. What is it intended for? Also, what is $INCFLAGS? On the other hand, `dir_config()` would prepend `-I` flags to $CPPFLAGS and `-L` flags to $LIBPATH, so it doesn't have issues with flags from `RbConfig`, albeit in a differently way. -- https://bugs.ruby-lang.org/