emulators/mame not linking on sparc64

[Connor McLaughlan <cont6pro3%gmail.com@localhost>]

Hi,

i am using pkgsrc-2020Q2 on NetBSD9/sparc64.

First the compilation of mame on sparc64 can not execute unless the
makefile is modified:
MAKE_ENV+=      PTR64=1

After the compilation of mame there are errors during linking
referencing alloca:

Linking mame64...
ld: ../../../../netbsd/bin/x64/Release/libbgfx.a(imgui_draw.o): in
function `ImDrawList::AddPolyline(ImVec2 const*, int, unsigned int,
bool, float)':
imgui_draw.cpp:(.text+0x2dc8): warning: Warning: reference to the libc
supplied alloca(3); this most likely will not work. Please use the
compiler provided version of alloca(3), by supplying the appropriate
compiler flags (e.g. not -std=c89).
ld: imgui_draw.cpp:(.text+0x2dc8): warning: Warning: reference to the
libc supplied alloca(3); this most likely will not work. Please use
the compiler provided version of alloca(3), by supplying the
appropriate compiler flags (e.g. not -std=c89).
ld: imgui_draw.cpp:(.text+0x2dc8): undefined reference to `alloca'
ld: ../../../../netbsd/bin/x64/Release/libbgfx.a(imgui_draw.o): in
function `ImDrawList::AddConvexPolyFilled(ImVec2 const*, int, unsigned
int)':
imgui_draw.cpp:(.text+0x3a40): undefined reference to `alloca'
ld: ../../../../netbsd/bin/x64/Release/libbgfx.a(bgfx.o): in function
`bgfx::fatal(char const*, unsigned short, bgfx::Fatal::Enum, char
const*, ...)':
bgfx.cpp:(.text+0x4054): undefined reference to `alloca'
ld: ../../../../netbsd/bin/x64/Release/libbgfx.a(bgfx.o): in function
`bgfx::TextVideoMem::printfVargs(unsigned short, unsigned short,
unsigned char, char const*, void*)':
bgfx.cpp:(.text+0x4378): undefined reference to `alloca'
ld: ../../../../netbsd/bin/x64/Release/libbgfx.a(bgfx.o): in function
`bgfx::CallbackStub::traceVargs(char const*, unsigned short, char
const*, void*)':
bgfx.cpp:(.text._ZN4bgfx12CallbackStub10traceVargsEPKctS2_Pv[_ZN4bgfx12CallbackStub10traceVargsEPKctS2_Pv]+0x84):
undefined reference to `alloca'
ld: ../../../../netbsd/bin/x64/Release/libbgfx.a(bgfx.o):bgfx.cpp:(.text._ZN4bgfx7Context12createShaderEPKNS_6MemoryE[_ZN4bgfx7Context12createShaderEPKNS_6MemoryE]+0x5a0):
more undefined references to `alloca' follow
gmake[2]: *** [mame.make:269: ../../../../../mame64] Error 1
gmake[1]: *** [Makefile:1105: mame] Error 2
gmake[1]: Leaving directory
'/usr/pkgsrc/emulators/mame/work/mame-mame0220/build/projects/sdl/mame/gmake-netbsd'
gmake: *** [makefile:1508: netbsd_x64] Error 2
*** Error code 2

Stop.
bmake[1]: stopped in /usr/pkgsrc/emulators/mame
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/emulators/mame

Regards,
Connor