I found a syntax error when compiling without threads.
In that place, the colon has been used instead of semicolon at end of statement.

build commands and error log:
$ uname -a
Linux masayuki-P35-DS3 4.4.0-83-generic #106-Ubuntu SMP Mon Jun 26 17:54:25 UTC 2017 i686 i686 i686 GNU/Linux
$ git checkout master
$ ./configure --without-threads && LC_ALL=C make -j2
(snip)
gcc -c -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes    -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration   -I. -I./Include    -DPy_BUILD_CORE -o Python/ceval.o Python/ceval.c
Python/ceval.c: In function 'Py_MakePendingCalls':
Python/ceval.c:551:23: error: expected ';' before ':' token
             goto error:
                       ^
Makefile:1551: recipe for target 'Python/ceval.o' failed
make: *** [Python/ceval.o] Error 1

related changeset:
3024c0529077f5cff0b32dc84b5923c8fba99a87 [3.6] bpo-30703: Improve signal delivery (GH-2415) (#2527)
c08177a1ccad2ed0d50898c2731b518c631aed14 bpo-30703: Improve signal delivery (#2415)

I open one line change PR that replaces colon with semicolon for master branch right away.