Makfile: PCRE2 default

Remove the USE_PCRE2 makefile variable so that the makefile's
configuration searches for PCRE2 and falls back to PCRE if not found.

makefile

@@ -603,27 +603,22 @@ ifeq (${WIN32},)  #*nix Environments (&& cygwin)
       LIBEXT = $(LIBEXTSAVE)
     endif
   endif
-  ## RegEx: Prefer the PCRE library over PCRE2 for historical reasons. Only detect
-  ## and use PCRE2 if USE_PCRE2 is set as a command line variable or in the
-  ## environment.
   FALLBACK_PCRE=yes
-  ifdef USE_PCRE2
-    # Find the PCRE2 RegEx library
-    ifneq (,$(call find_include,pcre2))
-      PCRE2_LIB=pcre2-8
-      ifneq (,$(call find_lib,${PCRE2_LIB}))
-	OS_CCDEFS += -DHAVE_PCRE2_H
-	OS_LDFLAGS += -l${PCRE2_LIB}
-        $(info using libpcre2-8: $(call find_lib,${PCRE2_LIB}) $(call find_include,pcre2))
-	ifeq ($(LD_SEARCH_NEEDED),$(call need_search,${PCRE2_LIB}))
-	  OS_LDFLAGS += -L$(dir $(call find_lib,${{PCRE2_LIB}}))
-	endif
-	FALLBACK_PCRE=
+  # Find the PCRE2 RegEx library
+  ifneq (,$(call find_include,pcre2))
+    PCRE2_LIB=pcre2-8
+    ifneq (,$(call find_lib,${PCRE2_LIB}))
+      OS_CCDEFS += -DHAVE_PCRE2_H
+      OS_LDFLAGS += -l${PCRE2_LIB}
+      $(info using libpcre2-8: $(call find_lib,${PCRE2_LIB}) $(call find_include,pcre2))
+      ifeq ($(LD_SEARCH_NEEDED),$(call need_search,${PCRE2_LIB}))
+	OS_LDFLAGS += -L$(dir $(call find_lib,${PCRE2_LIB}))
       endif
+      FALLBACK_PCRE=
     endif
-    ifneq ($(FALLBACK_PCRE),)
-      $(info *** Info *** PCRE2 not detected, falling back to PCRE)
-    endif
+  endif
+  ifneq ($(FALLBACK_PCRE),)
+    $(info *** Info *** PCRE2 not detected, falling back to PCRE)
   endif
   # Find PCRE RegEx library, either because we didn't want PCRE2 or we didn't
   # find PCRE2.