Remove --with-fp / --without-fp.

There is a configure option --without-fp that specifies that nofpu
sysdeps directories should be used instead of fpu directories.

For most glibc configurations, this option is of no use: either there
is no valid nofpu variant of that configuration, or there are no fpu
or nofpu sysdeps directories for that processor and so the option does
nothing.  For a few configurations, if you are using a soft-float
compiler this option is required, and failing to use it generally
results in compilation errors from inline asm using unavailable
floating-point instructions.

We're moving away from --with-cpu to configuring glibc based on how
the compiler generates code, and it is natural to do so for
--without-fp as well; in most cases the soft-float and hard-float ABIs
are incompatible so you have no hope of building a working glibc with
an inappropriately configured compiler or libgcc.

This patch eliminates --without-fp, replacing it entirely by automatic
configuration based on the compiler.  Configurations for which this is
relevant (coldfire / mips / powerpc32 / sh) define a variable
with_fp_cond in their preconfigure fragments (under the same
conditions under which those fragments do anything); this is a
preprocessor conditional which the toplevel configure script then uses
in a test to determine which sysdeps directories to use.

The config.make with-fp variable remains.  It's used only by powerpc
(sysdeps/powerpc/powerpc32/Makefile) to add -mhard-float to various
flags variables.  For powerpc, -mcpu= options can imply use of
soft-float.  That could be an issue if you want to build for
e.g. 476fp, but are using --with-cpu=476 because there isn't a 476fp
sysdeps directory.  If in future we eliminate --with-cpu and replace
it entirely by testing the compiler, it would be natural at that point
to eliminate that code as well (as the user should then just use a
compiler defaulting to 476fp and the 476 sysdeps directory would be
used automatically).

Tested for x86_64, and tested with build-many-glibcs.py that installed
shared libraries are unchanged by this patch.

	* configure.ac (--with-fp): Remove configure option.
	(with_fp_cond): New variable.
	(libc_cv_with_fp): New configure test.  Use this variable instead
	of with_fp.
	* configure: Regenerated.
	* config.make.in (with-fp): Use @libc_cv_with_fp@.
	* manual/install.texi (Configuring and compiling): Remove
	--without-fp.
	* INSTALL: Regenerated.
	* sysdeps/m68k/preconfigure (with_fp_cond): Define for ColdFire.
	* sysdeps/mips/preconfigure (with_fp_cond): Define.
	* sysdeps/powerpc/preconfigure (with_fp_cond): Define for 32-bit.
	* sysdeps/sh/preconfigure (with_fp_cond): Define.
	* scripts/build-many-glibcs.py (Context.add_all_configs): Do not
	use --without-fp to configure glibc.

4 files changed, 16 insertions, 3 deletions

diff --git a/sysdeps/m68k/preconfigure b/sysdeps/m68k/preconfigure
index 94fc1aabc2..1028dac080 100644
--- a/sysdeps/m68k/preconfigure
+++ b/sysdeps/m68k/preconfigure
@@ -13,5 +13,9 @@ m68k)		variant=`(echo "#ifdef __mcoldfire__"
 		  echo >&2 "Cannot determine m68k processor variant"
 		  exit 1
 		fi
-		base_machine=m68k machine=m68k/$variant ;;
+		base_machine=m68k machine=m68k/$variant
+		if test "$variant" = "coldfire"; then
+		  with_fp_cond="defined __mcffpu__"
+		fi
+		;;
 esac
diff --git a/sysdeps/mips/preconfigure b/sysdeps/mips/preconfigure
index c118592b27..48fc32ed5b 100644
--- a/sysdeps/mips/preconfigure
+++ b/sysdeps/mips/preconfigure
@@ -25,5 +25,7 @@ mips*)
 	if test "$abiflag" != "_ABIO32" -a "$mips16flag" = "1"; then
 		as_fn_error $? "MIPS16 is only supported with the o32 ABI." "$LINENO" 5
 	fi
+
+	with_fp_cond="defined __mips_hard_float"
 	;;
 esac
diff --git a/sysdeps/powerpc/preconfigure b/sysdeps/powerpc/preconfigure
index 7de2eafd52..0030bfd0c0 100644
--- a/sysdeps/powerpc/preconfigure
+++ b/sysdeps/powerpc/preconfigure
@@ -16,5 +16,6 @@ powerpc*)
     base_machine=powerpc machine=powerpc/powerpc32
   fi
   rm -f conftest.i
+  with_fp_cond="!defined __NO_FPRS__"
   ;;
 esac
diff --git a/sysdeps/sh/preconfigure b/sysdeps/sh/preconfigure
index c1f6537797..16e29273df 100644
--- a/sysdeps/sh/preconfigure
+++ b/sysdeps/sh/preconfigure
@@ -1,6 +1,12 @@
 # preconfigure fragment for sh.
 
 case "$machine" in
-sh3*)		base_machine=sh machine=sh/sh3 ;;
-sh4*)		base_machine=sh machine=sh/sh4 ;;
+sh3*)		base_machine=sh
+		machine=sh/sh3
+		with_fp_cond="defined __SH_FPU_ANY__"
+		;;
+sh4*)		base_machine=sh
+		machine=sh/sh4
+		with_fp_cond="defined __SH_FPU_ANY__"
+		;;
 esac