Trac #29071: verify if cblas.pc and lapack.pc should be replaced by l…

…inks to openblas.pc

currently openblas's spkg-configure.pc unconditionally makes cblas.pc
and lapack.pc copies of openblas.pc, which in some cases if incorrect,
e.g. Arch Linux has libcblas linked to libopenblas
and containing stuff missing in libopenblas, resulting in errors.

this has been reported on sage-devel
https://groups.google.com/d/msg/sage-devel/pIOnFyFJMtM/_FbzM2OxCQAJ

So we should make these installations conditional.

URL: https://trac.sagemath.org/29071
Reported by: dimpase
Ticket author(s): Dima Pasechnik
Reviewer(s): Isuru Fernando, Matthias Koeppe

build/pkgs/openblas/spkg-configure.m4

@@ -1,16 +1,34 @@
 SAGE_SPKG_CONFIGURE([openblas], [
+ SAGE_SPKG_DEPCHECK([gfortran], [
   PKG_CHECK_MODULES([OPENBLAS], [openblas >= 0.2.20], [
     PKG_CHECK_VAR([OPENBLASPCDIR], [openblas], [pcfiledir], [
-       AC_CONFIG_LINKS([
-         $SAGE_SRC/lib/pkgconfig/blas.pc:$OPENBLASPCDIR/openblas.pc
-         $SAGE_SRC/lib/pkgconfig/cblas.pc:$OPENBLASPCDIR/openblas.pc
-         $SAGE_SRC/lib/pkgconfig/lapack.pc:$OPENBLASPCDIR/openblas.pc])
+       sage_install_blas_pc=yes
+       AC_SEARCH_LIBS([cblas_dgemm], [openblas], [dnl openblas works as cblas
+             sage_install_cblas_pc=yes
+             ], [
+             dnl openblas does not work as cblas; try to use system's cblas as is
+             PKG_CHECK_MODULES([CBLAS], [cblas], [], [sage_spkg_install_openblas=yes])
+          ])
+       AC_FC_FREEFORM([AC_FC_FUNC([dgeqrf])])
+       AC_SEARCH_LIBS([$dgeqrf], [openblas], [dnl openblas works as lapack
+             sage_install_lapack_pc=yes
+             ], [
+             dnl openblas does not work as lapack; try to use system's lapack as is
+             PKG_CHECK_MODULES([LAPACK], [lapack], [], [sage_spkg_install_openblas=yes])
+          ])
        ], [
        AC_MSG_WARN([Unable to locate the directory of openblas.pc. This should not happen!])
        sage_spkg_install_openblas=yes
        ])
     ], [sage_spkg_install_openblas=yes])
-  ], [
+    AS_IF([test x$sage_spkg_install_openblas != xyes], [
+       m4_foreach([blaslibnam], [blas, cblas, lapack], [
+        AS_IF([test x$sage_install_]blaslibnam[_pc = xyes], [
+         AC_CONFIG_LINKS([$SAGE_SRC/lib/pkgconfig/]blaslibnam[.pc:$OPENBLASPCDIR/openblas.pc])])
+       ])
+    ])
+ ])
+ ], [
   AS_IF([test "x$with_blas" = xopenblas], [
      sage_require_openblas=yes
      sage_require_atlas=no])