build_tools/mkpkgconfig: Fix Cflags concatenation error in asterisk.pc

The mkpkgconfig script incorrectly concatenates Cflags options together. As an
example, the following:
Cflags: -I/usr/include/libxml2 -g3

Is instead generated as:
Cflags: -I/usr/include/libxml2-g3

This patch corrects the generation of Cflags in mkpkgconfig such that the
Cflags options are output correctly.

Review: https://reviewboard.asterisk.org/r/3707/

ASTERISK-23991 #close
Reported by: Diederik de Groot
patches:
  fix_mkpkgconfig.diff uploaded by Diederik de Groot (License 6600)
........

Merged revisions 430589 from http://svn.asterisk.org/svn/asterisk/branches/11
........

Merged revisions 430590 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@430591 65c4cc65-6c06-0410-ace0-fbb531ad65f3

build_tools/mkpkgconfig

@@ -22,13 +22,12 @@ else
 fi
 
 ## Clean out CFLAGS for the spec file.
-
-LOCAL_CFLAGS=`echo $CFLAGS | ${EXTREGEX} 's/\s*-pipe\s*//g' | ${EXTREGEX} 's/-[Wmp]\S*\s*//g' | \
-  ${EXTREGEX} 's/-I(include|\.\.\/include) //g' | \
+LOCAL_CFLAGS=`echo $CFLAGS | ${EXTREGEX} 's/-pipe\s*//g' | ${EXTREGEX} 's/-[Wmp]\S*\s*//g' | \
+  ${EXTREGEX} 's/\s+-I(include|\.\.\/include)\s+/ /g' | \
   ${EXTREGEX} 's/-DINSTALL_PREFIX=\S* //g' | \
   ${EXTREGEX} 's/-DASTERISK_VERSION=\S* //g' | \
-  ${EXTREGEX} 's/-DAST(ETCDIR|LIBDIR|VARLIBDIR|VARRUNDIR|SPOOLDIR|LOGDIR|CONFPATH|MODDIR|AGIDIR)=\S* //g'`
-
+  ${EXTREGEX} 's/-DAST(ETCDIR|LIBDIR|VARLIBDIR|VARRUNDIR|SPOOLDIR|LOGDIR|CONFPATH|MODDIR|AGIDIR)=\S* //g' | \
+  ${EXTREGEX} 's/^\s|\s$//g'`
 
 cat <<EOF > "$PPATH/asterisk.pc"
 install_prefix=$INSTALL_PREFIX