llvm-gcc-toolfile: remove -frounding-math for Clang

-frounding-math is not supported in Clang, thus remove it.
Tested with LLVM/Clang 3.5.0

clang: warning: optimization flag '-frounding-math' is not supported
[-Winvalid-command-line-argument]

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #1171 from davidlt/remove-clang-frounding-math

llvm-gcc-toolfile: remove -frounding-math for Clang
cgal,cgal-toolfile: add dependency on gmp-static and mpfr-static

Failures in Clang builds shows that CGAL actually needs to find GMP and
MPFR headers. Originally I compiled GMP and MPFR statically, then had
them as build time only dependency. The patch resolves Clang and ICC
build errors correctly.

There is already a partial fix on ICC:

    250dbe3a8d1df22f26eb625351c62d99ec629b02

Makes GMP and MPFR as 'Requires:' in CGAL. Then adds those dependencies
in CGAL toolfile.

Signed-off-by: David Abdurachmanov <David.Abdurachmanov@cern.ch>
Merge pull request #1172 from davidlt/resolve-cgal-failures-clang-icc

cgal,cgal-toolfile: add dependency on gmp-static and mpfr-static
Merge remote branch 'origin/IB/CMSSW_7_3_X/stable' into IB/CMSSW_7_0_X/stable