Merged in stefanc/premake-dev/gmake-parallel-pch (pull request #118)

Fix gmake parallel builds when using precompiled headers

src/actions/make/_make.lua

@@ -135,6 +135,11 @@
 		_p('# %s %s makefile autogenerated by Premake', premake.action.current().shortname, kind)
 		_p('')
 
+		if kind == "solution" then
+			_p('.NOTPARALLEL:')
+			_p('')
+		end
+
 		make.defaultconfig(target)
 
 		_p('ifndef verbose')

src/actions/make/make_cpp.lua

@@ -453,7 +453,7 @@
 
 	function make.pchRules(prj)
 		_p('ifneq (,$(PCH))')
-		_p('.NOTPARALLEL: $(GCH) $(PCH)')
+		_p('$(OBJECTS): $(GCH) $(PCH)')
 		_p('$(GCH): $(PCH)')
 		_p('\t@echo $(notdir $<)')
 

tests/actions/make/cpp/test_make_pch.lua

@@ -91,7 +91,7 @@
 		prepareRules()
 		test.capture [[
 ifneq (,$(PCH))
-.NOTPARALLEL: $(GCH) $(PCH)
+$(OBJECTS): $(GCH) $(PCH)
 $(GCH): $(PCH)
 	@echo $(notdir $<)
 	$(SILENT) $(CXX) -x c++-header $(ALL_CXXFLAGS) -o "$@" -MF "$(@:%.gch=%.d)" -c "$<"
@@ -110,7 +110,7 @@ endif
 		prepareRules()
 		test.capture [[
 ifneq (,$(PCH))
-.NOTPARALLEL: $(GCH) $(PCH)
+$(OBJECTS): $(GCH) $(PCH)
 $(GCH): $(PCH)
 	@echo $(notdir $<)
 	$(SILENT) $(CC) -x c-header $(ALL_CFLAGS) -o "$@" -MF "$(@:%.gch=%.d)" -c "$<"