The dependency on PCRE removed from Makefile.libs in gnur. It was probably a...

The dependency on PCRE removed from Makefile.libs in gnur. It was probably a forgotten dependency since
according to the GnuR release notes GnuR now requires an external version of PCRE.

com.oracle.truffle.r.native/gnur/Makefile.libs

@@ -32,7 +32,7 @@ BLAS_TARGET := $(TARGET_DIR)/libRblas$(DYLIB_EXT)
 LAPACK_TARGET := $(TARGET_DIR)/libRlapack$(DYLIB_EXT)
 PCRE_TARGET := $(TARGET_DIR)/libpcre$(DYLIB_EXT)
 
-all: $(TARGET_DIR) $(BLAS_TARGET) $(LAPACK_TARGET) $(PCRE_TARGET) 
+all: $(TARGET_DIR) $(BLAS_TARGET) $(LAPACK_TARGET)
 
 $(TARGET_DIR):
 	mkdir -p $(TARGET_DIR)