Add option to opt out of pkg-config during configuration

acinclude.m4

@@ -139,39 +139,44 @@ dnl  `-l' flag(s).  Else, straight up use lib-path and include-path.
 AC_DEFUN([FLINT_SET_LIBFLAGS],
 [tmpalias=m4_default([$4],[$1])
 
-if test "x$PKG_CONFIG" != "x" && test "x`$PKG_CONFIG --path $1`" != "x";
+if test "x$2" != "x";
 then
-    if test "x$2" != "x";
-    then
-        withpath="--with-path=$2"
-    else
-        withpath=""
-    fi
+    pkgconfigpath="PKG_CONFIG_PATH=$2/pkgconfig"
+fi
 
+if test "$enable_pkg_config" = "yes" && eval "$pkgconfigpath $PKG_CONFIG --path $1"; test "$?" = "0";
+then
     # libdir
-    tmp=`$PKG_CONFIG --variable=libdir $withpath $1` dnl ' Fix Vim syntax
+    tmp=`eval "$pkgconfigpath $PKG_CONFIG --variable=libdir $1"` dnl ' Fix Vim syntax
     eval ${tmpalias}_libdir="\${tmp}"
+    echo "libdir = $tmp"
 
     # includedir
-    tmp=`$PKG_CONFIG --variable=includedir $withpath $1` dnl ' Fix Vim syntax
+    tmp=`eval "$pkgconfigpath $PKG_CONFIG --variable=includedir $1"` dnl ' Fix Vim syntax
     eval ${tmpalias}_includedir="\${tmp}"
+    echo "includedir = $tmp"
 
     # LIBS
-    tmp=`$PKG_CONFIG --libs-only-l $withpath $1` dnl ' Fix Vim syntax
+    tmp=`eval "$pkgconfigpath $PKG_CONFIG --libs-only-l $1"` dnl ' Fix Vim syntax
     eval ${tmpalias}_LIBS="\${tmp}"
+    echo "LIBS = $tmp"
 
     # LDFLAGS
-    tmp=`$PKG_CONFIG --libs-only-L $withpath $1` dnl ' Fix Vim syntax
+    tmp=`eval "$pkgconfigpath $PKG_CONFIG --libs-only-L $1"` dnl ' Fix Vim syntax
     eval ${tmpalias}_LDFLAGS="\${tmp}"
+    echo "LDFLAGS = $tmp"
 
     # CPPFLAGS
-    tmp=`$PKG_CONFIG --cflags-only-other $withpath $1 | sed -n 's/\(-D\w\+\)\(\|=\w\+\)/\n\1\2\n/gp' | sed -n '/^-D/p'` dnl ' Fix Vim syntax
-    tmp="`$PKG_CONFIG --cflags-only-I $withpath $1` $tmp" dnl ' Fix Vim syntax
+    tmp=`eval "$pkgconfigpath $PKG_CONFIG --cflags-only-other $1" | sed -n 's/\(-D\w\+\)\(\|=\w\+\)/\n\1\2\n/gp' | sed -n '/^-D/p'` dnl ' Fix Vim syntax
+    tmp2=`eval "$pkgconfigpath $PKG_CONFIG --cflags-only-I $1"` dnl ' Fix Vim syntax
+    tmp="$tmp $tmp2"
     eval ${tmpalias}_CPPFLAGS="\${tmp}"
+    echo "CPPFLAGS = $tmp"
 
     # CFLAGS
-    tmp=`$PKG_CONFIG --cflags-only-other $withpath $1 | sed 's/\(-D\w\+\)\(\|=\w\+\)//g' | sed 's/  / /g'` dnl ' Fix Vim syntax
+    tmp=`eval "$pkgconfigpath $PKG_CONFIG --cflags-only-other $withpath $1" | sed 's/\(-D\w\+\)\(\|=\w\+\)//g' | sed 's/  / /g'` dnl ' Fix Vim syntax
     eval ${tmpalias}_CFLAGS="\${tmp}"
+    echo "CFLAGS = $tmp"
 else
     if test "x${2}" != "x";
     then

configure.ac

@@ -148,20 +148,6 @@ then
     CXXFLAGS=
 fi
 
-################################################################################
-# programs
-################################################################################
-
-dnl NOTE: The following line is invoked from LT_INIT
-dnl AC_PROG_CC
-
-AC_PROG_MKDIR_P
-AC_PATH_PROGS(PKG_CONFIG, [pkg-config pkgconf], [])
-AC_ARG_VAR([PKG_CONFIG], [path to pkg-config or pkgconf])
-
-FLINT_CC_IS_GCC
-FLINT_CC_IS_CLANG
-
 ################################################################################
 # build system
 ################################################################################
@@ -271,6 +257,17 @@ yes|no)
 esac],
 enable_dependency_tracking="yes")
 
+AC_ARG_ENABLE(pkg-config,
+[AS_HELP_STRING([--enable-pkg-config],[Enable finding dependency information via pkg-config [default=auto]])],
+[case $enableval in
+yes|no)
+    ;;
+*)
+    AC_MSG_ERROR([Bad value $enableval for --enable-pkg-config. Need yes or no.])
+    ;;
+esac],
+enable_pkg_config="yes")
+
 AC_ARG_ENABLE(pretty-tests,
 [AS_HELP_STRING([--enable-pretty-tests],[Enable pretty printing for tests [default=yes]])],
 [case $enableval in
@@ -349,6 +346,28 @@ yes|no)
 esac],
 enable_fast_build="no")
 
+################################################################################
+# programs
+################################################################################
+
+dnl NOTE: The following line is invoked from LT_INIT
+dnl AC_PROG_CC
+
+AC_PROG_MKDIR_P
+
+if test "$enable_pkg_config" = "yes";
+then
+    AC_PATH_PROGS(PKG_CONFIG, [pkg-config pkgconf], [])
+    if test "x$PKG_CONFIG" = "x";
+    then
+        enable_pkg_config="no"
+    fi
+fi
+AC_ARG_VAR([PKG_CONFIG], [path to pkg-config or pkgconf])
+
+FLINT_CC_IS_GCC
+FLINT_CC_IS_CLANG
+
 ################################################################################
 # library dependencies
 ################################################################################
@@ -543,6 +562,7 @@ done
 ################################################################################
 
 # FIXME: Not the prettiest solution for BLAS
+# FIXME: Fix Boehm GC
 
 for lib in $library_dependencies;
 do