Cannot build with mingw64

[cslycord]

Won't build with mingw64 gcc/toolchain.

Linker complains of "undefined reference to `__imp__snprintf.constprop.0'"

This is a mingw64 64-bit toolchain inside msys2.

make make all-recursive make[1]: Entering directory '/home/tony/gifsicle' Making all in src make[2]: Entering directory '/home/tony/gifsicle/src' gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT clp.o -MD -MP -MF .deps/clp.Tpo -c -o clp.o clp.c mv -f .deps/clp.Tpo .deps/clp.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT fmalloc.o -MD -MP -MF .deps/fmalloc.Tpo -c -o fmalloc.o fmalloc.c mv -f .deps/fmalloc.Tpo .deps/fmalloc.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT giffunc.o -MD -MP -MF .deps/giffunc.Tpo -c -o giffunc.o giffunc.c mv -f .deps/giffunc.Tpo .deps/giffunc.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT gifread.o -MD -MP -MF .deps/gifread.Tpo -c -o gifread.o gifread.c mv -f .deps/gifread.Tpo .deps/gifread.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT gifunopt.o -MD -MP -MF .deps/gifunopt.Tpo -c -o gifunopt.o gifunopt.c mv -f .deps/gifunopt.Tpo .deps/gifunopt.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT merge.o -MD -MP -MF .deps/merge.Tpo -c -o merge.o merge.c mv -f .deps/merge.Tpo .deps/merge.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT optimize.o -MD -MP -MF .deps/optimize.Tpo -c -o optimize.o optimize.c mv -f .deps/optimize.Tpo .deps/optimize.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT quantize.o -MD -MP -MF .deps/quantize.Tpo -c -o quantize.o quantize.c mv -f .deps/quantize.Tpo .deps/quantize.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT support.o -MD -MP -MF .deps/support.Tpo -c -o support.o support.c mv -f .deps/support.Tpo .deps/support.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT xform.o -MD -MP -MF .deps/xform.Tpo -c -o xform.o xform.c mv -f .deps/xform.Tpo .deps/xform.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT gifsicle.o -MD -MP -MF .deps/gifsicle.Tpo -c -o gifsicle.o gifsicle.c mv -f .deps/gifsicle.Tpo .deps/gifsicle.Po gcc -W -Wall -DHAVE_CONFIG_H -I. -I.. -I../include -g -O2 -MT gifwrite.o -MD -MP -MF .deps/gifwrite.Tpo -c -o gifwrite.o gifwrite.c mv -f .deps/gifwrite.Tpo .deps/gifwrite.Po gcc -W -Wall -g -O2 -o gifsicle.exe clp.o fmalloc.o giffunc.o gifread.o gifunopt.o merge.o optimize.o quantize.o support.o xform.o gifsicle.o gifwrite.o C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: gifsicle.o: in functiongifread_error':
C:\msys64\home\tony\gifsicle\src/gifsicle.c:547: undefined reference to __imp__snprintf.constprop.0' C:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: C:\msys64\home\tony\gifsicle\src/gifsicle.c:550: undefined reference to __imp__snprintf.constprop.0'
collect2.exe: error: ld returned 1 exit status
make[2]: *** [Makefile:385: gifsicle.exe] Error 1
make[2]: Leaving directory '/home/tony/gifsicle/src'
make[1]: *** [Makefile:452: all-recursive] Error 1
make[1]: Leaving directory '/home/tony/gifsicle'
make: *** [Makefile:350: all] Error 2`

[wjaguar]

Encountered the same problem today (gcc 10.2.0 in MXE), found a workaround based on this:
https://stackoverflow.com/questions/21936012/a-c-linking-error
Namely: feeding CFLAGS=-fno-ipa-cp-clone to ./configure gets rid of the error.

[wjaguar]

Correction: the above worked by coincidence - set CFLAGS preempted the default -O2.
The actual fix is either reducing the optimization level to -O1, or adding -fno-ipa-cp to -O2: CFLAGS='-O2 -fno-ipa-cp'