fix

GNUmakefile.llvm

@@ -43,7 +43,7 @@ endif
 LLVMVER  = $(shell $(LLVM_CONFIG) --version 2>/dev/null | sed 's/git//' | sed 's/svn//' )
 LLVM_MAJOR = $(shell $(LLVM_CONFIG) --version 2>/dev/null | sed 's/\..*//' )
 LLVM_MINOR = $(shell $(LLVM_CONFIG) --version 2>/dev/null | sed 's/.*\.//' | sed 's/git//' | sed 's/svn//' | sed 's/ .*//' )
-LLVM_UNSUPPORTED = $(shell $(LLVM_CONFIG) --version 2>/dev/null | egrep -q '^[0-2]\.|3\.[0-3]' && echo 1 || echo 0 )
+LLVM_UNSUPPORTED = $(shell $(LLVM_CONFIG) --version 2>/dev/null | egrep -q '^3\.[0-3]|^[0-2]\.' && echo 1 || echo 0 )
 LLVM_TOO_NEW = $(shell $(LLVM_CONFIG) --version 2>/dev/null | egrep -q '^1[3-9]' && echo 1 || echo 0 )
 LLVM_NEW_API = $(shell $(LLVM_CONFIG) --version 2>/dev/null | egrep -q '^1[0-9]' && echo 1 || echo 0 )
 LLVM_10_OK = $(shell $(LLVM_CONFIG) --version 2>/dev/null | egrep -q '^1[1-9]|^10\.[1-9]|^10\.0.[1-9]' && echo 1 || echo 0 )
@@ -59,7 +59,7 @@ ifeq "$(LLVMVER)" ""
 endif
 
 ifeq "$(LLVM_UNSUPPORTED)" "1"
-  $(warning llvm_mode only supports llvm versions 3.4 up to 12)
+  $(error llvm_mode only supports llvm from version 3.4 onwards)
 endif
 
 ifeq "$(LLVM_TOO_NEW)" "1"