pkg/54563: firefox 69.0.1 fails to build with clang

[ng0%n0.is@localhost]

>Number:         54563
>Category:       pkg
>Synopsis:       firefox 69.0.1 fails to build with clang
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Sep 23 06:10:00 +0000 2019
>Originator:     ng0
>Release:        current
>Organization:
>Environment:
NetBSD uptimegirl 9.99.11 NetBSD 9.99.11 (GENERIC) amd64
>Description:
on a system with clang from base and pkgsrc with clang, www/firefox fails to build with:

/usr/work/www/firefox/work/.cwrapper/bin/clang++ -o Decimal.o -c  -I/usr/work/www/firefox/work/build/dist/stl_wrappers -I/usr/work/www/firefox/work/build/dist/system_wrappers -include /usr/work/www/firefox/work/firefox-69.0.1/config/gcc_hidden.h -DNDEBUG=1 -DTRIMMED=1 -DMOZ_HAS_MOZGLUE -DIMPL_MFBT -I/usr/work/www/firefox/work/firefox-69.0.1/mozglue/misc -I/usr/work/www/firefox/work/build/mozglue/misc -I/usr/work/www/firefox/work/build/dist/include -I/usr/pkg/include/nspr -I/usr/pkg/include/nss -I/usr/pkg/include/nspr -I/usr/work/www/firefox/work/build/dist/include/nss -I/usr/X11R7/include/pixman-1 -fPIC -DPIC -DMOZILLA_CLIENT -include /usr/work/www/firefox/work/build/mozilla-config.h -Qunused-arguments -I/usr/pkg/include -I/usr/include -I/usr/pkg/include/nspr -I/usr/pkg/include/nss/nss -I/usr/X11R7/include -I/usr/X11R7/include/libdrm -I/usr/pkg/include/glib-2.0 -I/usr/pkg/include/gio-unix-2.0 -I/usr/pkg/lib/glib-2.0/include -I/usr/pkg/include/ffmpeg4 -I/usr/X11R7/include/freetype2 -U
 _FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fstack-protector-strong -Qunused-arguments -Wall -Wbitfield-enum-conversion -Wempty-body -Wignored-qualifiers -Woverloaded-virtual -Wpointer-arith -Wshadow-field-in-constructor-modified -Wsign-compare -Wtype-limits -Wunreachable-code -Wunreachable-code-return -Wwrite-strings -Wno-invalid-offsetof -Wclass-varargs -Wfloat-overflow-conversion -Wfloat-zero-conversion -Wloop-analysis -Wc++1z-compat -Wc++2a-compat -Wcomma -Wimplicit-fallthrough -Wstring-conversion -Wtautological-overlap-compare -Wtautological-unsigned-enum-zero-compare -Wtautological-unsigned-zero-compare -Wno-inline-new-delete -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=backend-plugin -Wno-error=return-std-move -Wno-error=atomic-alignment -Wformat -Wformat-security -Wno-gnu-zero-variadic-macro-arguments -Wno-unknown-warning-option -Wno-return-type-c-linkage -fno-sized-deallocation -O2 -I/usr/pkg/include/nspr -D_GLIBCXX_INCLUDE_NEXT_C_HEADERS -I/usr/pkg/includ
 e -I/usr/include -I/usr/pkg/include/nss/nss -I/usr/X11R7/include -I/usr/X11R7/include/libdrm -I/usr/pkg/include/glib-2.0 -I/usr/pkg/include/gio-unix-2.0 -I/usr/pkg/lib/glib-2.0/include -I/usr/pkg/include/ffmpeg4 -I/usr/X11R7/include/freetype2 -D__HAVE_INLINE___ISINF -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fno-exceptions -fno-strict-aliasing -Dunix -fno-rtti -ffunction-sections -fdata-sections -fno-exceptions -fno-math-errno -pthread -pipe -I/usr/pkg/include -O2 -fomit-frame-pointer -funwind-tables  -MD -MP -MF .deps/Decimal.o.pp  -Wno-implicit-fallthrough /usr/work/www/firefox/work/firefox-69.0.1/mozglue/misc/decimal/Decimal.cpp
In file included from /usr/work/www/firefox/work/firefox-69.0.1/mozglue/misc/decimal/Decimal.cpp:32:
In file included from /usr/work/www/firefox/work/firefox-69.0.1/mozglue/misc/decimal/moz-decimal-utils.h:16:
In file included from /usr/work/www/firefox/work/build/dist/include/mozilla/FloatingPoint.h:15:
In file included from /usr/work/www/firefox/work/build/dist/include/mozilla/MathAlgorithms.h:15:
In file included from /usr/work/www/firefox/work/build/dist/stl_wrappers/cmath:44:
In file included from /usr/work/www/firefox/work/build/dist/system_wrappers/cmath:3:
/usr/include/c++/cmath:393:12: error: use of undeclared identifier '__isinf'
    return isinf(__lcpp_x);
           ^
/usr/include/math.h:484:20: note: expanded from macro 'isinf'
#define isinf(__x)      __isinf(__x)
                        ^
/usr/include/c++/cmath:403:12: note: in instantiation of function template specialization '__libcpp_isinf<double>' requested here
    return __libcpp_isinf((typename std::__promote<_A1>::type)__lcpp_x);
           ^
/usr/work/www/firefox/work/firefox-69.0.1/mozglue/misc/decimal/Decimal.cpp:698:14: note: in instantiation of function template specialization 'isinf<double>' requested here
    if (std::isinf(doubleValue))
             ^
1 error generated.
gmake[3]: *** [/usr/work/www/firefox/work/firefox-69.0.1/config/rules.mk:803: Decimal.o] Error 1
gmake[3]: Leaving directory '/usr/work/www/firefox/work/build/mozglue/misc'
gmake[2]: *** [/usr/work/www/firefox/work/firefox-69.0.1/config/recurse.mk:74: mozglue/misc/target] Error 2
gmake[2]: Leaving directory '/usr/work/www/firefox/work/build'
gmake[1]: *** [/usr/work/www/firefox/work/firefox-69.0.1/config/recurse.mk:34: compile] Error 2
gmake[1]: Leaving directory '/usr/work/www/firefox/work/build'
gmake: *** [/usr/work/www/firefox/work/firefox-69.0.1/config/rules.mk:391: all] Error 2
*** Error code 2

Stop.
make[1]: stopped in /usr/pkgsrc/www/firefox
*** Error code 1

Stop.
make: stopped in /usr/pkgsrc/www/firefox

>How-To-Repeat:

>Fix: