Default to using libpcre and actually use it

as libpcre has to better binary support.

Note, just linking libpcre only has no effect, the posix functions are
provided by libpcreposix.

Use "make USELIBPCRE=" to turn libpcre off and link POSIX library.

Makefile

@@ -3,7 +3,7 @@
 VERSION=$(shell ./genver.sh -r)
 ENABLE_REGEX=1  # Enable regex probes
 USELIBCONFIG=1	# Use libconfig? (necessary to use configuration files)
-USELIBPCRE=	# Use libpcre? (needed for regex on musl)
+USELIBPCRE=1	# Use libpcre? (needed for regex on musl)
 USELIBWRAP?=	# Use libwrap?
 USELIBCAP=	# Use libcap?
 USESYSTEMD=     # Make use of systemd socket activation
@@ -38,7 +38,7 @@ endif
 
 ifneq ($(strip $(USELIBPCRE)),)
 	CPPFLAGS+=-DLIBPCRE
-	LIBS:=$(LIBS) -lpcre
+	LIBS:=$(LIBS) -lpcreposix
 endif
 
 ifneq ($(strip $(USELIBCONFIG)),)