Windows: Revert to default paths and convert them by RUNTIME_PREFIX

The RUNTIME_PREFIX mechanism allows us to use the default paths on
Windows too.  Defining RUNTIME_PREFIX explicitly requests for
translation of paths relative to the executable at runtime.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -789,6 +789,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	SNPRINTF_RETURNS_BOGUS = YesPlease
 	NO_SVN_TESTS = YesPlease
 	NO_PERL_MAKEMAKER = YesPlease
+	RUNTIME_PREFIX = YesPlease
 	NO_POSIX_ONLY_PROGRAMS = YesPlease
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/regex -Icompat/fnmatch
@@ -797,9 +798,6 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	COMPAT_OBJS += compat/mingw.o compat/fnmatch/fnmatch.o compat/regex/regex.o compat/winansi.o
 	EXTLIBS += -lws2_32
 	X = .exe
-	gitexecdir = ../libexec/git-core
-	template_dir = ../share/git-core/templates/
-	ETC_GITCONFIG = ../etc/gitconfig
 endif
 ifneq (,$(findstring arm,$(uname_M)))
 	ARM_SHA1 = YesPlease