Merge pull request #18910 from JuliaLang/anj/osx

Fix build for macOS Sierra + LLVM 3.9.

DISTRIBUTING.md

@@ -104,9 +104,10 @@ completely self-contained Julia.app.
 
 Note that if you want your `.app` to be able to run on OSX 10.6 Snow
 Leopard, you must pass `USE_SYSTEM_LIBUNWIND=1` as one of the make
-variables passed to both `make` processes.  This disables the use of
+variables passed to both `make` processes. This disables the use of
 `libosxunwind`, a more modern libunwind that relies on OS features
-available only in 10.7+. This is the reason why we support 10.7+ [while we did support 10.6 prior to Julia 0.3.0](http:https://julialang.org/downloads/platform.html).
+available only in 10.7+. Furthermore, support for OSX 10.6 and 10.7
+requires that Julia is built with `USE_LIBCPP=0`.
 
 Windows
 -------

Make.inc

@@ -403,12 +403,14 @@ DEBUGFLAGS := -O0 -g -DJL_DEBUG_BUILD -fstack-protector-all
 SHIPFLAGS := -O3 -g
 ifeq ($(OS), Darwin)
 ifeq ($(USE_LIBCPP), 1)
-CC += -stdlib=libc++ -mmacosx-version-min=10.7
-CXX += -stdlib=libc++ -mmacosx-version-min=10.7
-FC += -mmacosx-version-min=10.7
+MACOSX_VERSION_MIN := 10.8
+CC += -stdlib=libc++ -mmacosx-version-min=$(MACOSX_VERSION_MIN)
+CXX += -stdlib=libc++ -mmacosx-version-min=$(MACOSX_VERSION_MIN)
+FC += -mmacosx-version-min=$(MACOSX_VERSION_MIN)
 else
-CC += $(STDLIBCPP_FLAG) -mmacosx-version-min=10.6
-CXX += $(STDLIBCPP_FLAG) -mmacosx-version-min=10.6
+MACOSX_VERSION_MIN := 10.6
+CC += $(STDLIBCPP_FLAG) -mmacosx-version-min=$(MACOSX_VERSION_MIN)
+CXX += $(STDLIBCPP_FLAG) -mmacosx-version-min=$(MACOSX_VERSION_MIN)
 endif
 JCPPFLAGS += -D_LARGEFILE_SOURCE -D_DARWIN_USE_64_BIT_INODE=1
 endif