Do not use pywin32 to get cpu_count while building

setup/build_environment.py

@@ -40,16 +40,6 @@ PKGCONFIG = os.environ.get('PKG_CONFIG', PKGCONFIG)
 if islinux and not PKGCONFIG:
     raise SystemExit('Failed to find pkg-config on your system. You can use the environment variable PKG_CONFIG to point to the pkg-config executable')
 
-if iswindows:
-    import win32api
-    cpu_count = win32api.GetSystemInfo()[5]
-else:
-    from multiprocessing import cpu_count
-    try:
-        cpu_count = cpu_count()
-    except NotImplementedError:
-        cpu_count = 1
-
 def run_pkgconfig(name, envvar, default, flag, prefix):
     ans = []
     if envvar:

setup/extensions.py

@@ -13,10 +13,10 @@ from setup import Command, islinux, isbsd, isosx, SRC, iswindows, __version__
 from setup.build_environment import (
     chmlib_inc_dirs, podofo_inc, podofo_lib, podofo_error, pyqt, NMAKE, QMAKE,
     msvc, win_inc, win_lib, chmlib_lib_dirs, sqlite_inc_dirs, icu_inc_dirs,
-    icu_lib_dirs, ft_libs, ft_lib_dirs, ft_inc_dirs, cpu_count, is64bit,
+    icu_lib_dirs, ft_libs, ft_lib_dirs, ft_inc_dirs, is64bit,
     glib_flags, fontconfig_flags, openssl_inc_dirs, openssl_lib_dirs,
     zlib_inc_dirs, zlib_lib_dirs, zlib_libs, qmakespec)
-from setup.parallel_build import create_job, parallel_build
+from setup.parallel_build import create_job, parallel_build, cpu_count
 isunix = islinux or isosx or isbsd
 
 make = 'make' if isunix else NMAKE

setup/parallel_build.py

@@ -11,7 +11,37 @@ from multiprocessing.dummy import Pool
 from functools import partial
 from contextlib import closing
 
-from setup.build_environment import cpu_count
+from setup import iswindows
+
+if iswindows:
+    from ctypes import windll, Structure, POINTER, c_size_t
+    from ctypes.wintypes import WORD, DWORD, LPVOID
+    class SYSTEM_INFO(Structure):
+        _fields_ = [
+            ("wProcessorArchitecture",      WORD),
+            ("wReserved",                   WORD),
+            ("dwPageSize",                  DWORD),
+            ("lpMinimumApplicationAddress", LPVOID),
+            ("lpMaximumApplicationAddress", LPVOID),
+            ("dwActiveProcessorMask",       c_size_t),
+            ("dwNumberOfProcessors",        DWORD),
+            ("dwProcessorType",             DWORD),
+            ("dwAllocationGranularity",     DWORD),
+            ("wProcessorLevel",             WORD),
+            ("wProcessorRevision",          WORD)]
+    gsi = windll.kernel32.GetSystemInfo
+    gsi.argtypes = [POINTER(SYSTEM_INFO)]
+    gsi.restype = None
+    si = SYSTEM_INFO()
+    gsi(si)
+    cpu_count = min(16, max(1, si.dwNumberOfProcessors))
+else:
+    from multiprocessing import cpu_count
+    try:
+        cpu_count = cpu_count()
+    except NotImplementedError:
+        cpu_count = 1
+
 
 def run_worker(job, decorate=True):
     cmd, human_text = job