Reduce use of PCRE linker flags differently

... to make our SunOS vtest build happy again

ld: fatal: file /opt/local/lib/libpcre.so: wrong ELF class: ELFCLASS64
ld: fatal: file processing errors. No output written to vjsn_test
collect2: error: ld returned 1 exit status

The issue here was order of the -L -l arguments when a (32bit) version
of a library needs to be found first in an overridden LDPATH.

Ref 12bbe31f
Ref #3559

lib/libvarnish/Makefile.am

@@ -6,7 +6,7 @@ AM_CPPFLAGS = \
 	@PCRE_CFLAGS@
 
 AM_CFLAGS   = $(AM_LT_CFLAGS)  @SAN_CFLAGS@
-AM_LDFLAGS  = $(AM_LT_LDFLAGS) @SAN_LDFLAGS@ @PCRE_LIBS@
+AM_LDFLAGS  = $(AM_LT_LDFLAGS) @SAN_LDFLAGS@
 
 noinst_LTLIBRARIES = libvarnish.la
 
@@ -44,6 +44,8 @@ libvarnish_la_SOURCES = \
 	vtim.c \
 	vus.c
 
+libvarnish_la_LIBADD = @PCRE_LIBS@
+
 TESTS = vjsn_test vnum_c_test vbh_test vsb_test
 
 noinst_PROGRAMS = ${TESTS}