Using BUILDTOOLS_PATH to use nasm from existing copy of build tools

Source commit: e0e72c8ff19a900872d51f08e8819056d042b077

libs/openssl/Makefile

@@ -39,7 +39,11 @@ CP=copy
 RM=del
 MKDIR=-mkdir
 MKLIB=tlib /P128 /C
-ASM=..\..\buildtools\tools\nasm -f obj -d__omf__
+
+!ifndef BUILDTOOLS_PATH
+BUILDTOOLS_PATH=..\..\buildtools
+!endif
+ASM=$(BUILDTOOLS_PATH)\tools\nasm -f obj -d__omf__
 
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