meas: Unbreak the build once more

The code assumes that sqlite3.h is in the standard include
path. Maybe sqlite3 wasn't installed or resides in a non
standard (/usr/local) location? Fix the build as it has been
broken since 1st of January.
diff --git a/openbsc/configure.ac b/openbsc/configure.ac
index 3e5ae38..00d1b70 100644
--- a/openbsc/configure.ac
+++ b/openbsc/configure.ac
@@ -88,6 +88,11 @@
 AC_CHECK_HEADERS(cdk/cdk.h,,found_cdk=no)
 AM_CONDITIONAL(HAVE_LIBCDK, test "$found_cdk" = yes)
 
+found_sqlite3=yes
+PKG_CHECK_MODULES(SQLITE3, sqlite3, ,found_sqlite3=no)
+AM_CONDITIONAL(HAVE_SQLITE3, test "$found_sqlite3" = yes)
+AC_SUBST(found_sqlite3)
+
 
 dnl Checks for typedefs, structures and compiler characteristics