[complib:mpfr] Fix building MPFR in some weird cases

The tmul test uses a compiled-in input file in $(srcdir).
The problem is that the Makefile passes it unquoted. The C code
tries to stringify it using clever macros, which may *usually* work.

In my case the source directory was named:
.../toolchain-powerpc-e500v2-linux-gnuspe-1.0-2.fc10/.../tests
And guess what? During testing I found out the program fails because
it tries to open:
.../toolchain-powerpc-e500v2-1-gnuspe-1.0-2.fc10/.../tests

Yes, CPP tokenized the macro before stringifying it and not surprisingly
the 'linux' part was converted to 1.
[on Fedora-10: cpp (GCC) 4.3.2 20081105 (Red Hat 4.3.2-7)]

So the attached patch simplify the macros and pass the path as string
from the Makefile.

 diff -dur strace-4.5.15.orig/process.c strace-4.5.15/process.c

 --- strace-4.5.15.orig/process.c	2007-01-11 23:08:38.000000000 +0100

 +++ strace-4.5.15/process.c	2007-07-14 19:19:58.000000000 +0200

 @@ -2679,7 +2679,6 @@

         { 4*REG_GBR,            "4*REG_GBR"                             },

         { 4*REG_MACH,           "4*REG_MACH"                            },

         { 4*REG_MACL,           "4*REG_MACL"                            },

 -       { 4*REG_SYSCALL,        "4*REG_SYSCALL"                         },

         { 4*REG_FPUL,           "4*REG_FPUL"                            },

         { 4*REG_FPREG0,         "4*REG_FPREG0"                          },

         { 4*(REG_FPREG0+1),     "4*REG_FPREG1"                          },