Record full paths of programs sought by "configure".

Previously we had a mix of uses of AC_CHECK_PROG[S] and AC_PATH_PROG[S].
The only difference between those macros is that the latter emits the
full path to the program it finds, eg "/usr/bin/prove", whereas the
former emits just "prove".  Let's standardize on always emitting the
full path; this is better for documentation of the build, and it might
prevent some types of failures if later build steps are done with
a different PATH setting.

I did not touch the AC_CHECK_PROG[S] calls in ax_pthread.m4 and
ax_prog_perl_modules.m4.  There seems no need to make those diverge from
upstream, since we do not record the programs sought by the former, while
the latter's call to AC_CHECK_PROG(PERL,...) will never be reached.

Discussion: https://postgr.es/m/25937.1501433410@sss.pgh.pa.us

config/docbook.m4

@@ -3,7 +3,7 @@
 # PGAC_PROG_NSGMLS
 # ----------------
 AC_DEFUN([PGAC_PROG_NSGMLS],
-[AC_CHECK_PROGS([NSGMLS], [onsgmls nsgmls])])
+[AC_PATH_PROGS([NSGMLS], [onsgmls nsgmls])])
 
 
 # PGAC_CHECK_DOCBOOK(VERSION)

config/programs.m4

@@ -229,7 +229,7 @@ AC_DEFUN([PGAC_CHECK_GETTEXT],
                  [AC_MSG_ERROR([a gettext implementation is required for NLS])])
   AC_CHECK_HEADER([libintl.h], [],
                   [AC_MSG_ERROR([header file <libintl.h> is required for NLS])])
-  AC_CHECK_PROGS(MSGFMT, msgfmt)
+  AC_PATH_PROGS(MSGFMT, msgfmt)
   if test -z "$MSGFMT"; then
     AC_MSG_ERROR([msgfmt is required for NLS])
   fi
@@ -238,8 +238,8 @@ AC_DEFUN([PGAC_CHECK_GETTEXT],
     pgac_cv_msgfmt_flags=-c
 fi])
   AC_SUBST(MSGFMT_FLAGS, $pgac_cv_msgfmt_flags)
-  AC_CHECK_PROGS(MSGMERGE, msgmerge)
-  AC_CHECK_PROGS(XGETTEXT, xgettext)
+  AC_PATH_PROGS(MSGMERGE, msgmerge)
+  AC_PATH_PROGS(XGETTEXT, xgettext)
 ])# PGAC_CHECK_GETTEXT
 
 

configure.in

@@ -218,15 +218,15 @@ PGAC_ARG_BOOL(enable, profiling, no,
 #
 PGAC_ARG_BOOL(enable, coverage, no,
               [build with coverage testing instrumentation],
-[AC_CHECK_PROGS(GCOV, gcov)
+[AC_PATH_PROGS(GCOV, gcov)
 if test -z "$GCOV"; then
   AC_MSG_ERROR([gcov not found])
 fi
-AC_CHECK_PROGS(LCOV, lcov)
+AC_PATH_PROGS(LCOV, lcov)
 if test -z "$LCOV"; then
   AC_MSG_ERROR([lcov not found])
 fi
-AC_CHECK_PROGS(GENHTML, genhtml)
+AC_PATH_PROGS(GENHTML, genhtml)
 if test -z "$GENHTML"; then
   AC_MSG_ERROR([genhtml not found])
 fi])
@@ -237,7 +237,7 @@ AC_SUBST(enable_coverage)
 #
 PGAC_ARG_BOOL(enable, dtrace, no,
               [build with DTrace support],
-[AC_CHECK_PROGS(DTRACE, dtrace)
+[AC_PATH_PROGS(DTRACE, dtrace)
 if test -z "$DTRACE"; then
   AC_MSG_ERROR([dtrace not found])
 fi
@@ -816,7 +816,7 @@ PGAC_ARG_BOOL(with, libxml, no, [build with XML support],
               [AC_DEFINE([USE_LIBXML], 1, [Define to 1 to build with XML support. (--with-libxml)])])
 
 if test "$with_libxml" = yes ; then
-  AC_CHECK_PROGS(XML2_CONFIG, xml2-config)
+  AC_PATH_PROGS(XML2_CONFIG, xml2-config)
   if test -n "$XML2_CONFIG"; then
     for pgac_option in `$XML2_CONFIG --cflags`; do
       case $pgac_option in
@@ -2119,17 +2119,17 @@ fi
 #
 PGAC_PROG_NSGMLS
 PGAC_CHECK_DOCBOOK(4.2)
-AC_CHECK_PROGS(DBTOEPUB, dbtoepub)
-AC_CHECK_PROGS(XMLLINT, xmllint)
-AC_CHECK_PROGS(XSLTPROC, xsltproc)
-AC_CHECK_PROGS(OSX, [osx sgml2xml sx])
-AC_CHECK_PROGS(FOP, fop)
+AC_PATH_PROGS(DBTOEPUB, dbtoepub)
+AC_PATH_PROGS(XMLLINT, xmllint)
+AC_PATH_PROGS(XSLTPROC, xsltproc)
+AC_PATH_PROGS(OSX, [osx sgml2xml sx])
+AC_PATH_PROGS(FOP, fop)
 
 #
 # Check for test tools
 #
 if test "$enable_tap_tests" = yes; then
-  AC_CHECK_PROGS(PROVE, prove)
+  AC_PATH_PROGS(PROVE, prove)
   if test -z "$PROVE"; then
     AC_MSG_ERROR([prove not found])
   fi