Make the jump-table section-relative for x86_64 with PIC enabled.

This allows to get rid of the macho64 specific hack that moves them
to rodata (with worse cache behaviour) and avoids textrels which
e.g. Gentoo does not allow for x86_64 libraries.

Originally committed as revision 21551 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/x86/fft_mmx.asm

@@ -419,18 +419,23 @@ DECL_PASS pass_interleave_3dn, PASS_BIG 0
 %define pass_3dn2 pass_3dn
 %define pass_interleave_3dn2 pass_interleave_3dn
 
+%ifdef PIC
+%define SECTION_REL - $$
+%else
+%define SECTION_REL
+%endif
 
 %macro DECL_FFT 2-3 ; nbits, cpu, suffix
-%xdefine list_of_fft fft4%2, fft8%2
+%xdefine list_of_fft fft4%2 SECTION_REL, fft8%2 SECTION_REL
 %if %1==5
-%xdefine list_of_fft list_of_fft, fft16%2
+%xdefine list_of_fft list_of_fft, fft16%2 SECTION_REL
 %endif
 
 %assign n 1<<%1
 %rep 17-%1
 %assign n2 n/2
 %assign n4 n/4
-%xdefine list_of_fft list_of_fft, fft %+ n %+ %3%2
+%xdefine list_of_fft list_of_fft, fft %+ n %+ %3%2 SECTION_REL
 
 align 16
 fft %+ n %+ %3%2:
@@ -448,10 +453,6 @@ fft %+ n %+ %3%2:
 %endrep
 %undef n
 
-%ifidn __OUTPUT_FORMAT__,macho64
-section .rodata
-%endif
-
 align 8
 dispatch_tab%3%2: pointer list_of_fft
 
@@ -462,6 +463,10 @@ section .text
 cglobal fft_dispatch%3%2, 2,5,8, z, nbits
     lea r2, [dispatch_tab%3%2 GLOBAL]
     mov r2, [r2 + (nbitsq-2)*gprsize]
+%ifdef PIC
+    lea r3, [$$ GLOBAL]
+    add r2, r3
+%endif
     call r2
     RET
 %endmacro ; DECL_FFT