Make:Allow for extension in tool names.

In some build environments executable programs have a specific file
extension.  The value of BIN_EXT is appended to the relevant tool file
names to allow for this.
The value of BIN_EXT is set, where appropriate, by the build environment
specific make helper (to .exe for Windows build environments).

.gitignore is updated to hide the new (.exe) files.

Change-Id: Icc32f64b750e425265075ad4e0dea18129640b86
diff --git a/Makefile b/Makefile
index c20bf91..828ff57 100644
--- a/Makefile
+++ b/Makefile
@@ -377,11 +377,11 @@
 
 # Variables for use with Certificate Generation Tool
 CRTTOOLPATH		?=	tools/cert_create
-CRTTOOL			?=	${CRTTOOLPATH}/cert_create
+CRTTOOL			?=	${CRTTOOLPATH}/cert_create${BIN_EXT}
 
 # Variables for use with Firmware Image Package
 FIPTOOLPATH		?=	tools/fip_create
-FIPTOOL			?=	${FIPTOOLPATH}/fip_create
+FIPTOOL			?=	${FIPTOOLPATH}/fip_create${BIN_EXT}
 
 
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