[PATCH] Makefile: clarify runtime relative gitexecdir

["Đoàn Trần Công Danh" <congdanhqx@gmail.com>]

"git" built with RUNTIME_PREFIX flag turned on could figure out
gitexecdir and other paths as relative to "git" executable.

However, in the section specifies gitexecdir, RUNTIME_PREFIX wasn't
mentioned, thus users may wrongly assume that "git" always locates
gitexecdir as relative path to the executable.

Let's clarify that only "git" built with RUNTIME_PREFIX will locate
gitexecdir as relative path.

Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
---
 Makefile | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index cac3452edb..8a58be440f 100644
--- a/Makefile
+++ b/Makefile
@@ -529,8 +529,9 @@ GIT-VERSION-FILE: FORCE
 #   template_dir
 #   sysconfdir
 # can be specified as a relative path some/where/else;
-# this is interpreted as relative to $(prefix) and "git" at
-# runtime figures out where they are based on the path to the executable.
+# this is interpreted as relative to $(prefix) and "git" built with
+# RUNTIME_PREFIX flag will figure out (at runtime) where they are
+# based on the path to the executable.
 # Additionally, the following will be treated as relative by "git" if they
 # begin with "$(prefix)/":
 #   mandir
-- 
2.38.0.1.ge44e9fe867