Fix #78460: PEAR installation failure

When building PHP outside of the source tree:

  mkdir custom-build-dir
  cd custom-build-dir
  ../path/to/php-src/configure

The directories need to be manually created including the pear directory
so the pear installation PHAR file doesn't need to be downloaded from
the remote location.

Closes GH-4639

Author: petk

configure.ac

@@ -1550,6 +1550,8 @@ PHP_GEN_GLOBAL_MAKEFILE
 
 AC_DEFINE([HAVE_BUILD_DEFS_H], 1, [ ])
 
+dnl Make directories when building in a separate build directory.
+$php_shtool mkdir -p pear
 $php_shtool mkdir -p scripts
 $php_shtool mkdir -p scripts/man1