Allow running pic_flag test with different shell.

[Ralf Wildenhues]

I'd like to ensure that $CONFIG_SHELL and $configure_options are used
consistently throughout the testsuite.  So I'm fixing the pic_flag test
to also use LT_AT_CONFIGURE, after making that macro accept a second
argument to specify another configure script location.

Hope this is trivial enough to just push it, please complain otherwise.

Thanks,
Ralf

    Allow running pic_flag test with different shell.
    
    * tests/testsuite.at (LT_AT_CONFIGURE): Accept optional second
    argument specifying the configure script to run.
    * tests/pic_flag.at (override pic_flag at configure time):
    Use LT_AT_CONFIGURE.

diff --git a/tests/pic_flag.at b/tests/pic_flag.at
index e62e1b7..c045ed4 100644
--- a/tests/pic_flag.at
+++ b/tests/pic_flag.at
@@ -43,8 +43,9 @@ if $CXX $CPPFLAGS $CXXFLAGS $CXX_pic_flag -c foo.cpp; then :; 
else
   CXX_pic_flag=
 fi
 
-AT_CHECK(["$abs_top_srcdir"/configure lt_cv_prog_compiler_pic="$C_pic_flag" 
]dnl
-        [lt_cv_prog_compiler_pic_CXX="$CXX_pic_flag"], [], [ignore], [ignore])
+LT_AT_CONFIGURE([lt_cv_prog_compiler_pic="$C_pic_flag" ]dnl
+               [lt_cv_prog_compiler_pic_CXX="$CXX_pic_flag"],
+               ["$abs_top_srcdir"/configure])
 : ${MAKE=make}
 AT_CHECK([$MAKE], [], [stdout], [ignore])
 AT_CHECK([if ./libtool --features | grep 'enable shared libraries'; then ]dnl
diff --git a/tests/testsuite.at b/tests/testsuite.at
index 3935962..35b920b 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -146,11 +146,13 @@ AT_KEYWORDS([autoconf automake])
 ])
 
 
-# LT_AT_CONFIGURE([OPTIONS])
-# --------------------------
+# LT_AT_CONFIGURE([OPTIONS], [CONFIGURE-SCRIPT])
+# ----------------------------------------------
+# Configure CONFIGURE-SCRIPT, defaulting to ./configure, with
+# additional OPTIONS.
 m4_define([LT_AT_CONFIGURE],
 [AT_CHECK([: ${CONFIG_SHELL=/bin/sh}; export CONFIG_SHELL; ]dnl
-         [$CONFIG_SHELL ./configure $configure_options $1],
+         [$CONFIG_SHELL m4_default([$2], [./configure]) $configure_options $1],
          [0], [ignore], [ignore])
 ])