Something

liquid@water:~/openwrt/trunk$ svn diff
Index: toolchain/uClibc/Makefile
===================================================================
--- toolchain/uClibc/Makefile   (revision 5294)
+++ toolchain/uClibc/Makefile   (working copy)
@@ -52,6 +52,9 @@
 ifeq ($(CONFIG_SOFT_FLOAT),y)
        $(SED) 's,.*HAS_FPU.*,HAS_FPU=n\nUCLIBC_HAS_FLOATS=y\nUCLIBC_HAS_SOFT_FLOAT=y,g' $(PKG_BUILD_DIR)/.config
 endif
+ifeq ($(CONFIG_C99_MATH),y)
+       $(SED) 's,.*DO_C99_MATH.*,DO_C99_MATH=y,g' $(PKG_BUILD_DIR)/.config
+endif
        mkdir -p $(TOOLCHAIN_BUILD_DIR)/uClibc_dev/usr/include
        mkdir -p $(TOOLCHAIN_BUILD_DIR)/uClibc_dev/usr/lib
        mkdir -p $(TOOLCHAIN_BUILD_DIR)/uClibc_dev/lib
Index: toolchain/Config.in
===================================================================
--- toolchain/Config.in (revision 5294)
+++ toolchain/Config.in (working copy)
@@ -26,8 +26,15 @@
        depends on !cris
        default y
        help
-           Enable large file (files > 2 GB) support
+               Enable large file (files > 2 GB) support

+config C99_MATH
+       bool
+       prompt "Enable full C99 math support?" if TOOLCHAINOPTS
+       default n
+       help
+               Enable if you need full C99 math in libm
+
 config SOFT_FLOAT
        bool
        prompt "Use software floating point by default" if TOOLCHAINOPTS