[folks] Soften the valadoc requirement, even with --enable-docs.

[Travis Reitter <treitter src gnome org>]

commit 4ae86ad3a83d57e166a667ce992f672092b8a0eb
Author: Travis Reitter <travis reitter collabora co uk>
Date:   Tue Nov 9 15:38:16 2010 -0800

    Soften the valadoc requirement, even with --enable-docs.
    
    This is mainly so tarball-based builds don't break if valadoc isn't availble
    (but it will be used if it is).
    
    Helps bgo#633718.

 Makefile.am  |    2 +-
 configure.ac |    7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index b7aec36..786b4f1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -8,7 +8,7 @@ SUBDIRS = \
 	po \
 	$(NULL)
 
-if ENABLE_DOCS
+if HAVE_VALADOC
 SUBDIRS += docs
 endif
 
diff --git a/configure.ac b/configure.ac
index 4fdfd3a..d1e2b94 100644
--- a/configure.ac
+++ b/configure.ac
@@ -154,8 +154,9 @@ AM_CONDITIONAL([ENABLE_DOCS], [test x$enable_docs = xyes])
 
 AS_IF([test "x$enable_docs" != xno],
       [AC_PATH_PROG([VALADOC], [valadoc], [:])
-       AS_IF([test "$VALADOC" = :],
-             [AC_MSG_ERROR([valadoc not found])])])
+       AS_IF([test "$VALADOC" != :],
+             have_valadoc=yes)])
+AM_CONDITIONAL([HAVE_VALADOC], [test x$have_valadoc = xyes])
 
 # -----------------------------------------------------------
 # Gettext
@@ -262,7 +263,7 @@ Configure summary:
         Compiler Flags..............:  ${CFLAGS} ${ERROR_CFLAGS}
         Prefix......................:  ${prefix}
         Bugreporting URL............:  ${PACKAGE_BUGREPORT}
-        Documentation...............:  ${enable_docs}
+        Documentation...............:  ${HAVE_VALADOC}
         Tests.......................:  ${have_tp_glib_for_tests}
         Import tool.................:  ${with_import_tool}