commit 83f868ea8decbbe97891631fe142e84c883ee33d
Author: Ilya Tumaykin <itumaykin@gmail.com>
Date:   Wed Jun 1 20:00:37 2016 +0300

Allow to build and run tests with a system copy of gtest (googletest)

Also add LIBS_UCHARDET to the mix only when uchardet is requested.

Closes #1923

Bug: http://devel.aegisub.org/ticket/1923
---

diff --git a/configure.ac b/configure.ac
index 856e38993..197d0a788 100644
--- a/configure.ac
+++ b/configure.ac
@@ -144,7 +144,7 @@ AS_IF([test x$enable_compiler_flags != xno], [
   CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wno-unused-parameter -fno-strict-aliasing"
 
   # For mac compiler which still stuck on c++98
-  AC_CXX_FLAG([-std=c++11])
+  AC_CXX_FLAG([-std=c++14])
 
   # -O* messes with debugging.
   AS_IF([test x$enable_debug = xyes], [
diff --git a/tests/Makefile b/tests/Makefile
index 137430854..bafb59a0f 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,24 +1,46 @@
 include $(dir $(lastword $(MAKEFILE_LIST)))../header.mk
 
+WITH_SYSTEM_GTEST ?= no
+
+ifeq (no, $(WITH_SYSTEM_GTEST))
 GTEST_ROOT ?= $(TOP)vendor/googletest
 GTEST_FILE := ${GTEST_ROOT}/src/gtest-all
+GTEST_CPPFLAGS := -I$(GTEST_ROOT) -I$(GTEST_ROOT)/include
+GTEST_LIBS := $(LIBS_PTHREAD)
+else
+GTEST_CPPFLAGS := $(shell ${PKG_CONFIG} --cflags-only-I gtest)
+GTEST_LIBS := $(shell ${PKG_CONFIG} --libs gtest)
+endif
+
+GTEST_CXXFLAGS := $(CFLAGS_PTHREAD)
 
 run_PCH := $(d)support/tests_pre.h
 run_CPPFLAGS := -I$(TOP)libaegisub/include -I$(TOP) -I$(d)support \
-	-I$(GTEST_ROOT) -I$(GTEST_ROOT)/include $(CPPFLAGS_BOOST) $(CFLAGS_LUA)
-run_CXXFLAGS := -Wno-unused-value -Wno-sign-compare
-run_LIBS := $(LIBS_BOOST) $(LIBS_ICU) $(LIBS_UCHARDET) $(LIBS_PTHREAD)
+	$(CPPFLAGS_BOOST) $(CFLAGS_LUA) $(GTEST_CPPFLAGS)
+run_CXXFLAGS := -Wno-unused-value -Wno-sign-compare $(GTEST_CXXFLAGS)
+run_LIBS := $(LIBS_BOOST) $(LIBS_ICU) $(LIBS_UCHARDET) $(LIBS_PTHREAD) $(GTEST_LIBS)
 run_OBJ := \
 	$(patsubst %.cpp,%.o,$(wildcard $(d)tests/*.cpp)) \
 	$(d)support/main.o \
 	$(d)support/util.o \
-	$(TOP)lib/libaegisub.a \
-	$(GTEST_FILE).o
+	$(TOP)lib/libaegisub.a
+
+ifeq (yes, $(HAVE_UCHARDET))
+run_LIBS += $(LIBS_UCHARDET)
+endif
+
+ifeq (no, $(WITH_SYSTEM_GTEST))
+run_OBJ += $(GTEST_FILE).o
 
 # This bit of goofiness is to make it only try to build the tests if google
 # test can be found and silently skip it if not, by using $(wildcard) to check
 # for file existence
 PROGRAM += $(subst $(GTEST_FILE).cc,$(d)run,$(wildcard $(GTEST_FILE).cc))
+test: $(subst $(GTEST_FILE).cc,test-libaegisub,$(wildcard $(GTEST_FILE).cc))
+else
+PROGRAM += $(d)run
+test: test-libaegisub
+endif
 
 ifeq (yes, $(BUILD_DARWIN))
 run_LIBS += -framework ApplicationServices -framework Foundation
@@ -31,6 +53,4 @@ gtest_filter ?= *
 test-libaegisub: $(d)run $(d)data
 	cd $(TOP)tests; ./run --gtest_filter="$(gtest_filter)"
 
-test: $(subst $(GTEST_FILE).cc,test-libaegisub,$(wildcard $(GTEST_FILE).cc))
-
 include $(TOP)Makefile.target