[libvirt] [PATCH] virt-wireshark.m4: Defer $(prefix) substitution

[Michal Privoznik]

The problem with evaluating $(prefix) in configure phase is that
autoconf does a lot of magic with this variable. Firstly, if the
--prefix argument is not set for the configure script, the
variable will have value "NONE". Wait, wat? Secondly, even
autoconf scripts then have special cases for when variable is
"NONE". It's even worse - whenever they need to construct new
path based on prefix, they save its current value, substitute it
with proper value (like /usr/local/), do what they need and then
restore the original value. Le sigh.
This mad behaviour is, however, suppressed if there's --prefix on
the configure command line.
Now, the problem is that we tried to construct path for wireshark
plugin in the m4 file. Based on the knowledge described above, we
shouldn't do it and just construct the full path in Makefile
later where prefix has proper value.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 m4/virt-wireshark.m4 | 2 +-
 tools/Makefile.am    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/m4/virt-wireshark.m4 b/m4/virt-wireshark.m4
index f383e2b..e1e4a59 100644
--- a/m4/virt-wireshark.m4
+++ b/m4/virt-wireshark.m4
@@ -38,7 +38,7 @@ AC_DEFUN([LIBVIRT_CHECK_WIRESHARK],[
         if test "x$ws_prefix" = "x" ; then
           ws_prefix="/usr";
         fi
-        plugindir="${prefix}${plugindir#$ws_prefix}"
+        plugindir="${plugindir#$ws_prefix}"
       fi
     elif test "x$with_ws_plugindir" = "xno" || test "x$with_ws_plugindir" = "xyes"; then
       AC_MSG_ERROR([ws-plugindir must be used only with valid path])
diff --git a/tools/Makefile.am b/tools/Makefile.am
index e7e42c3..08e1680 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -398,7 +398,7 @@ EXTRA_DIST += \
 
 if WITH_WIRESHARK_DISSECTOR
 
-ws_plugindir = $(plugindir)
+ws_plugindir = $(prefix)$(plugindir)
 ws_plugin_LTLIBRARIES = wireshark/src/libvirt.la
 wireshark_src_libvirt_la_CPPFLAGS = \
 	-I wireshark/src $(WIRESHARK_DISSECTOR_CFLAGS)
-- 
2.8.4