tools/build: Introduce {PREPEND,APPEND}_{LIB,INCLUDES}

Create two new variables called APPEND_ and PREPEND_ to add compile
flags at the beginning or at the end of the search path.

Added a new semantic for user defined compile flags, here is the list
of possible options:

PREPEND_LIB: add libraries to the search path before xen
             (before xen installation folders).
PREPEND_INCLUDES: add headers to the search path before xen
                  (before xen installation folders).
APPEND_LIB: add libraries to the search path at the end
            (after all xen installation folders have been added).
APPEND_INCLUDES: add libraries to the search path at the end
                 (after all xen installation folders have been added).

EXTRA_INCLUDES and EXTRA_LIB can still be used, and they will have the
same effect as PREPEND_INCLUDES and PREPEND_LIB.

Signed-off-by: Roger Pau Monne <roger.pau@entel.upc.edu>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Config.mk b/Config.mk
index 0c4dfc84c4..9d137dfb21 100644
--- a/Config.mk
+++ b/Config.mk
@@ -171,6 +171,10 @@ $(call cc-option-add,CFLAGS,CC,-Wno-unused-but-set-variable)
 
 LDFLAGS += $(foreach i, $(EXTRA_LIB), -L$(i)) 
 CFLAGS += $(foreach i, $(EXTRA_INCLUDES), -I$(i))
+LDFLAGS += $(foreach i, $(PREPEND_LIB), -L$(i))
+CFLAGS += $(foreach i, $(PREPEND_INCLUDES), -I$(i))
+APPEND_LDFLAGS += $(foreach i, $(APPEND_LIB), -L$(i))
+APPEND_CFLAGS += $(foreach i, $(APPEND_INCLUDES), -I$(i))
 
 EMBEDDED_EXTRA_CFLAGS := -nopie -fno-stack-protector -fno-stack-protector-all
 EMBEDDED_EXTRA_CFLAGS += -fno-exceptions