Merge branch 'msys2-htmldir'

Git for Windows ships with a subset of MSYS2, and tries to integrate
smoothly, so we want to install the documentation in the location that
is recommended by MSYS2.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

config.mak.uname

@@ -616,7 +616,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NATIVE_CRLF = YesPlease
 	X = .exe
 ifneq (,$(wildcard ../THIS_IS_MSYSGIT))
-	htmldir = doc/git/html/
+	htmldir = share/doc/git/$(firstword $(subst -, ,$(GIT_VERSION)))/html
 	prefix =
 	INSTALL = /bin/install
 	EXTLIBS += /mingw/lib/libz.a