[cheese] Use AC_PROG_SED in configure.ac

[David King <davidk src gnome org>]

commit a703da2c79a2b9c187fca4e86e1e8d1527a565a6
Author: David King <amigadave amigadave com>
Date:   Sat Oct 25 11:29:49 2014 +0100

    Use AC_PROG_SED in configure.ac

 Makefile.am  |    2 +-
 configure.ac |    1 +
 2 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 2cde675..cd93049 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -463,7 +463,7 @@ test-report perf-report full-report: $(check_PROGRAMS)
          echo '  <version>$(PACKAGE_VERSION)</version>' >> $  xml ; \
          echo "  <revision>$$REVISION</revision>" >> $  xml ; \
          echo '</info>' >> $  xml ; \
-         sed '1,1s/^<?xml\b[^>?]*?>//' < test-log.xml >> $  xml ; \
+         $(SED) '1,1s/^<?xml\b[^>?]*?>//' < test-log.xml >> $  xml ; \
          rm test-log.xml ; \
          echo >> $  xml ; \
          echo '</report-collection>' >> $  xml ; \
diff --git a/configure.ac b/configure.ac
index 500fd69..dc1aff8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,6 +18,7 @@ AM_SILENT_RULES([yes])
 # Check for programs
 AC_PROG_CC
 AM_PROG_CC_C_O
+AC_PROG_SED
 AM_PROG_VALAC([0.25.2])
 
 # Initialize libtool