Check Apache HTTP Server command-line utility (#14173)

The Apache HTTP server command-line tool (/usr/sbin/apache2) might be
part of a separate package, such as apache2-bin or similar. If not
installed, the configure script can still find the apxs tool, but
previously didn't check for the HTTP server tool separately. Otherwise,
configure syntax errors (integer expression expected) are thrown when
checking for the Apache version.

build/php.m4

@@ -2040,6 +2040,7 @@ dnl
 dnl This macro is used to get a comparable version for Apache.
 dnl
 AC_DEFUN([PHP_AP_EXTRACT_VERSION],[
+AS_IF([test -x "$1"], [
   ac_output=`$1 -v 2>&1 | grep version | $SED -e 's/Oracle-HTTP-//'`
   ac_IFS=$IFS
 IFS="- /.
@@ -2049,6 +2050,7 @@ IFS="- /.
 
   APACHE_VERSION=`expr [$]4 \* 1000000 + [$]5 \* 1000 + [$]6`
 ])
+])
 
 dnl
 dnl PHP_CONFIG_NICE(filename)

sapi/apache2handler/config.m4

@@ -34,6 +34,11 @@ if test "$PHP_APXS2" != "no"; then
 
   APXS_INCLUDEDIR=`$APXS -q INCLUDEDIR`
   APXS_HTTPD=`$APXS -q SBINDIR`/`$APXS -q TARGET`
+  AS_IF([test ! -x "$APXS_HTTPD"], [AC_MSG_ERROR([m4_normalize([
+    $APXS_HTTPD executable not found. Please, install Apache HTTP Server
+    command-line utility.
+  ])])])
+
   APXS_CFLAGS=`$APXS -q CFLAGS`
   APU_BINDIR=`$APXS -q APU_BINDIR`
   APR_BINDIR=`$APXS -q APR_BINDIR`