cc/gcc: remove --enable-symver option

That option is coming from the original crosstool, and is not entirely
understand here.

Moreover, it breaks with newer gcc-s: 4.6.1 now breaks while configuring
libjava (and probably some other libs as well, untested).

There is an related bug report to the gcc BZ:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49555

If need be, the old behavior can be restored with:
CC_CORE_EXTRA_CONFIG_ARRAY="--enable-symver=gnu"
CC_EXTRA_CONFIG_ARRAY="--enable-symver=gnu"

Reported-by: Bryan Hundven <bryanhundven@gmail.com>
Reviewed-by: Bryan Hundven <bryanhundven@gmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
(transplanted from b24ead1a59472195f5b2071ff70664c36fa21c3f)

 # mingw32 config options

 # depends on EXPERIMENTAL && ( ARCH_x86 && ARCH_32 )

 config KERNEL_mingw32

     select MINGW32

     help

       Build a toolchain targeting systems running Windows as host

 choice

     bool

     prompt "Windows api version"

 # Don't remove next line

 # CT_INSERT_VERSION_BELOW

 config W32API_V_3_14

     bool

     prompt "3.14"

 config W32API_V_select

     bool

     prompt "Other version"

 endchoice

 config W32API_VERSION

     string

     prompt "W32 api version" if W32API_V_select

 # Don't remove next line

 # CT_INSERT_VERSION_STRING_BELOW

     default "3.14" if W32API_V_3_14

     help

       Enter the version number of the windows api files to use