Defined missing symbols in bla_rotg.c

Details:
- Defined local equivalents of libf2c's r_sign(), d_sign(), c_abs(), and
  z_abs(), which are needed by bla_rotg.c. Also defined r_abs() and
  d_abs() for completeness. Thanks to Vladimir Sukharev for reporting
  these bugs.

frame/compat/f2c/util/bla_d_abs.c

@@ -0,0 +1,48 @@
+/*
+
+   BLIS    
+   An object-based framework for developing high-performance BLAS-like
+   libraries.
+
+   Copyright (C) 2013, The University of Texas
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are
+   met:
+    - Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    - Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    - Neither the name of The University of Texas nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include "blis.h"
+
+#ifdef BLIS_ENABLE_BLAS2BLIS
+
+double bla_d_abs(doublereal *x)
+{
+	if(*x >= 0)
+		return(*x);
+
+	return(- *x);
+}
+
+#endif
+