Ticket #54198: gcc7+with_libgcc+libcxx.diff

lang/gcc7/Portfile

@@ -277 +277 @@
     depends_lib-delete path:lib/libgcc/libgcc_s.1.dylib:libgcc
 }
 
+foreach cdv {{} 3.9 4.0} {
+    set cv [join [split ${cdv} "."] ""]
+    if {${cdv} eq {}} {
+        variant libcxx description "Build to use libc++ and the corresponding headers from Xcode" {}
+    } else {
+        variant libcxx${cv} description "Build to use libc++ and the corresponding headers from port:clang-${cdv}" {}
+    }
+    if {[variant_isset libcxx${cv}]} {
+        if {${cdv} ne {}} {
+            depends_run-append  port:clang-${cdv}
+            set libcxx_headers "${prefix}/libexec/llvm-${cdv}/include/c++/v1"
+        } else {
+            set libcxx_headers "[file dir [exec xcrun --find clang]]/../include/c++/v1"
+        }
+        patchfiles-append   patch-use-libcxx.diff
+        post-patch {
+            reinplace "s|@LLVMHEADERPATH@|${libcxx_headers}|g" ${worksrcpath}/gcc/incpath.c
+        }
+
+        # GCC_IS_BUILDING_ITSELF: causes g++ to add a static libstdc++ just like it does when building with/for libstdc++
+        # GCC_FORCE_LIBSTDCPP: forces the use of libstdc++ for the current build and ignores the default clang C++ header location
+        # LIBCPP_INCLUDE_PATH: redefines the location of the clang C++ headers; empty means don't use them at all
+        # The combination below means: build GCC "as usual" itself
+        configure.env-append    GCC_IS_BUILDING_ITSELF=1 GCC_FORCE_LIBSTDCPP=1
+        build.env-append        GCC_IS_BUILDING_ITSELF=1 GCC_FORCE_LIBSTDCPP=1
+        destroot.env-append     GCC_IS_BUILDING_ITSELF=1 GCC_FORCE_LIBSTDCPP=1
+    }
+}
+
 post-destroot {
     file delete ${destroot}${prefix}/share/info/dir
 
@@ -309 +338 @@
     }
     ## end default gcc7 variant
     }
+    foreach cdv {{} 3.9 4.0} {
+        set cv [join [split ${cdv} "."] ""]
+        if {[variant_isset libcxx${cv}]} {
+            # move the stdc++ headers out of the way
+            xinstall -m 755 -d ${destroot}${prefix}/include/${name}-stdinc
+            file rename ${destroot}${prefix}/include/${name}/c++ ${destroot}${prefix}/include/${name}-stdinc/c++
+        }
+    }
 }
 
 select.group        gcc