ENH: split up internals of wmake/scripts/have_XXX functions

- adds some more flexibility

wmake/scripts/have_readline

@@ -20,7 +20,7 @@
 #     None
 #
 # Functions provided
-#     have_readline, no_readline, echo_readline
+#     have_readline, no_readline, echo_readline, search_readline
 #
 # Variables set on success
 #     HAVE_LIBREADLINE - as per GNU autoconf
@@ -32,7 +32,7 @@
 
 #------------------------------------------------------------------------------
 
-# Reset variables
+# Reset
 no_readline()
 {
     unset HAVE_LIBREADLINE READLINE_INC_DIR READLINE_LIB_DIR
@@ -48,17 +48,18 @@ echo_readline()
 }
 
 
+# Search
+# $1 : prefix (*_ARCH_PATH, system, ...)
+#
 # On success, return 0 and export variables
 # -> HAVE_LIBREADLINE, READLINE_INC_DIR, READLINE_LIB_DIR
-have_readline()
+search_readline()
 {
     local warn # warn="==> skip readline"
-    local settings
-
-    # Expected location, include/library names
-    local prefix=system
     local incName="readline/readline.h"
     local libName="libreadline"
+
+    local prefix="${1:-system}"
     local header library
 
     # ----------------------------------
@@ -104,7 +105,16 @@ have_readline()
 }
 
 
-# Reset variables
+# Output as per search_* function
+have_readline()
+{
+    search_readline system
+}
+
+
+#------------------------------------------------------------------------------
+
+# Reset
 no_readline
 
 # Test/query