https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84554
--- Comment #4 from matthew.hambley at metoffice dot gov.uk --- I have further information. From the build log: (long paths reduced with ellipses) .../gcc-8.2.0-build/./prev-gcc/xgcc -B.../gcc/8.2.0/x86_64-pc-linux-gnu/sys-include -DTIME_WITH_SYS_TIME=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_LOCALE_H=1 -DHAVE_WCHAR_H=1 -DHAVE_STDARG=1 -DHAVE_SYS_TIME_H=1 -DHAVE_STRUCT_LCONV_DECIMAL_POINT=1 -DHAVE_STRUCT_LCONV_THOUSANDS_SEP=1 -DHAVE_ALLOCA_H=1 -DHAVE_STDINT_H=1 -DHAVE_VA_COPY=1 -DHAVE_SETLOCALE=1 -DHAVE_GETTIMEOFDAY=1 -DHAVE_LONG_LONG=1 -DHAVE_INTMAX_T=1 -DMPFR_HAVE_INTMAX_MAX=1 -DMPFR_HAVE_FESETROUND=1 -DHAVE_DENORMS=1 -DHAVE_SIGNEDZ=1 -DHAVE_ROUND=1 -DHAVE_TRUNC=1 -DHAVE_FLOOR=1 -DHAVE_CEIL=1 -DHAVE_NEARBYINT=1 -DHAVE_LDOUBLE_IEEE_EXT_LITTLE=1 -DMPFR_USE_THREAD_SAFE=1 -DMPFR_USE_C11_THREAD_SAFE=1 -DHAVE_CLOCK_GETTIME=1 -DLT_OBJDIR=\".libs/\" -DHAVE_ATTRIBUTE_MODE=1 -DHAVE___GMPN_ROOTREM=1 -DHAVE___GMPN_SBPI1_DIVAPPR_Q=1 -I. -I../../../gcc-8.2.0/mpfr/tests -DSRCDIR='"../../../gcc-8.2.0/mpfr/tests"' -I../../../gcc-8.2.0/mpfr/src -I../src -I.../gcc-8.2.0-build/./gmp -DNO_ASM -g -O2 -MT tversion.o -MD -MP -MF .deps/tversion.Tpo -c -o tversion.o ../../../gcc-8.2.0/mpfr/tests/tversion.c mv -f .deps/tversion.Tpo .deps/tversion.Po /bin/sh ../libtool --tag=CC --mode=link .../gcc-8.2.0-build/./prev-gcc/xgcc -B.../gcc-8.2.0-build/./prev-gcc/ -B.../gcc/8.2.0/x86_64-pc-linux-gnu/bin/ -B.../gcc/8.2.0/x86_64-pc-linux-gnu/bin/ -B.../gcc/8.2.0/x86_64-pc-linux-gnu/lib/ -isystem .../gcc/8.2.0/x86_64-pc-linux-gnu/include -isystem .../gcc/8.2.0/x86_64-pc-linux-gnu/sys-include -DNO_ASM -g -O2 -no-install -L../src/.libs -static-libstdc++ -static-libgcc -o tversion tversion.o libfrtests.la -lm ../src/libmpfr.la -lgmp Notice that when tversion is compiled the argument "-I.../gcc-8.2.0-build/./gmp" is specified which explains why it uses the correct headers. Further notice that when it is linked there is no corresponding "big Ell" argument meaning that the "little Ell" reference to "gmp" will be satisfied elsewhere. Am I missing something when I configure the build?
