How to concatenate GNU GAS macro arguments with other tokens to make single label?

things like

\argA\()\argB :

should create a label composed by argA and argB.

EDIT

Testing, \() seems to be not necessary; the test code was:

    .file   "test.c"

.macro prova argA, argB
\argA\argB :
 .endm
    .text
.globl main
    .type   main, @function
main:
    leal    4(%esp), %ecx
    andl    $-16, %esp
    pushl   -4(%ecx)
    pushl   %ebp
    movl    %esp, %ebp
    pushl   %ecx
    movl    $0, %eax
    popl    %ecx
    popl    %ebp
    leal    -4(%ecx), %esp
        prova abc, def
        jmp  abcdef
    ret
    .size   main, .-main
    .ident  "GCC: (GNU) 4.3.2"
    .section    .note.GNU-stack,"",@progbits

which is just gcc -S test.c output (lazyness:D) of a minimal C code. (prova means test in italian)

What's your favorite gas assembler reference?

The docs cover this one quite well https://sourceware.org/binutils/docs/as/Macro.html

The string `()' can be used to separate the end of a macro argument from the following text. eg:

.macro opcode base length
    \base\().\length
.endm