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/tools/cert_create/Makefile b/tools/cert_create/Makefile
index 8218ab7..27545ba 100644
--- a/tools/cert_create/Makefile
+++ b/tools/cert_create/Makefile
@@ -32,7 +32,7 @@
 PLAT		:= none
 V		:= 0
 DEBUG		:= 0
-BINARY		:= ${PROJECT}
+BINARY		:= ${PROJECT}${BIN_EXT}
 OPENSSL_DIR	:= /usr
 
 OBJECTS := src/cert.o \