diff --git a/setup.py b/setup.py
index 018a8d80d..9e4b99c21 100755
--- a/setup.py
+++ b/setup.py
@@ -142,11 +142,11 @@ def get_sanitize_args(cc, ccver):
 
 class Env:
 
-    def __init__(self, cc, cflags, ldflags, ldpaths=[]):
-        self.cc, self.cflags, self.ldflags, self.ldpaths = cc, cflags, ldflags, ldpaths
+    def __init__(self, cc, cppflags, cflags, ldflags, ldpaths=[]):
+        self.cc, self.cppflags, self.cflags, self.ldflags, self.ldpaths = cc, cppflags, cflags, ldflags, ldpaths
 
     def copy(self):
-        return Env(self.cc, list(self.cflags), list(self.ldflags), list(self.ldflags))
+        return Env(self.cc, list(self.cppflags), list(self.cflags), list(self.ldflags), list(self.ldflags))
 
 
 def init_env(
@@ -166,14 +166,23 @@ def init_env(
         df += ' -Og'
     optimize = df if debug or sanitize else '-O3'
     sanitize_args = get_sanitize_args(cc, ccver) if sanitize else set()
+    cppflags = os.environ.get(
+        'OVERRIDE_CPPFLAGS', (
+            '-D_XOPEN_SOURCE=700 -D{}DEBUG'
+        ).format(
+            ('' if debug else 'N'),
+        )
+    )
+    cppflags = shlex.split(cppflags) + shlex.split(
+        sysconfig.get_config_var('CPPFLAGS')
+    )
     cflags = os.environ.get(
         'OVERRIDE_CFLAGS', (
-            '-Wextra -Wno-missing-field-initializers -Wall -std=c99 -D_XOPEN_SOURCE=700'
-            ' -pedantic-errors -Werror {} {} -D{}DEBUG -fwrapv {} {} -pipe {} -fvisibility=hidden'
+            '-Wextra -Wno-missing-field-initializers -Wall -std=c99'
+            ' -pedantic-errors -Werror {} {} -fwrapv {} {} -pipe {} -fvisibility=hidden'
         ).format(
             optimize,
             ' '.join(sanitize_args),
-            ('' if debug else 'N'),
             stack_protector,
             missing_braces,
             '-march=native' if native_optimizations else '',
@@ -184,13 +193,14 @@ def init_env(
     )
     if os.path.exists('.git'):
         rev = subprocess.check_output(['git', 'rev-parse', 'HEAD']).decode('utf-8').strip()
-        cflags.append('-DKITTY_VCS_REV="{}"'.format(rev))
+        cppflags.append('-DKITTY_VCS_REV="{}"'.format(rev))
     ldflags = os.environ.get(
         'OVERRIDE_LDFLAGS',
         '-Wall ' + ' '.join(sanitize_args) + ('' if debug else ' -O3')
     )
     ldflags = shlex.split(ldflags)
     ldflags.append('-shared')
+    cppflags += shlex.split(os.environ.get('CPPFLAGS', ''))
     cflags += shlex.split(os.environ.get('CFLAGS', ''))
     ldflags += shlex.split(os.environ.get('LDFLAGS', ''))
     if not debug and not sanitize:
@@ -198,10 +208,10 @@ def init_env(
         cflags.append('-flto'), ldflags.append('-flto')
 
     if profile:
-        cflags.append('-DWITH_PROFILER')
+        cppflags.append('-DWITH_PROFILER')
         cflags.append('-g3')
         ldflags.append('-lprofiler')
-    return Env(cc, cflags, ldflags)
+    return Env(cc, cppflags, cflags, ldflags)
 
 
 def kitty_env():
@@ -210,8 +220,9 @@ def kitty_env():
     cflags.append('-pthread')
     # We add 4000 to the primary version because vim turns on SGR mouse mode
     # automatically if this version is high enough
-    cflags.append('-DPRIMARY_VERSION={}'.format(version[0] + 4000))
-    cflags.append('-DSECONDARY_VERSION={}'.format(version[1]))
+    cppflags = ans.cppflags
+    cppflags.append('-DPRIMARY_VERSION={}'.format(version[0] + 4000))
+    cppflags.append('-DSECONDARY_VERSION={}'.format(version[1]))
     at_least_version('harfbuzz', 1, 5)
     cflags.extend(pkg_config('libpng', '--cflags-only-I'))
     if is_macos:
@@ -348,13 +359,13 @@ def compile_c_extension(kenv, module, incremental, compilation_database, all_key
 
     for original_src, dest in zip(sources, objects):
         src = original_src
-        cflgs = kenv.cflags[:]
+        cppflgs = kenv.cppflags[:]
         is_special = src in SPECIAL_SOURCES
         if is_special:
             src, defines = SPECIAL_SOURCES[src]
-            cflgs.extend(map(define, defines))
+            cppflgs.extend(map(define, defines))
 
-        cmd = [kenv.cc, '-MMD'] + cflgs
+        cmd = [kenv.cc, '-MMD'] + kenv.cflags + cppflgs
         key = original_src, os.path.basename(dest)
         all_keys.add(key)
         cmd_changed = compilation_database.get(key, [])[:-4] != cmd
@@ -482,23 +493,25 @@ def build_asan_launcher(args):
 
 def build_linux_launcher(args, launcher_dir='.', for_bundle=False, sh_launcher=False):
     cflags = '-Wall -Werror -fpie'.split()
+    cppflags = []
     libs = []
     if args.profile:
-        cflags.append('-DWITH_PROFILER'), cflags.append('-g')
+        cppflags.append('-DWITH_PROFILER'), cflags.append('-g')
         libs.append('-lprofiler')
     else:
         cflags.append('-O3')
     if for_bundle:
-        cflags.append('-DFOR_BUNDLE')
-        cflags.append('-DPYVER="{}"'.format(sysconfig.get_python_version()))
+        cppflags.append('-DFOR_BUNDLE')
+        cppflags.append('-DPYVER="{}"'.format(sysconfig.get_python_version()))
     elif sh_launcher:
-        cflags.append('-DFOR_LAUNCHER')
-    cflags.append('-DLIB_DIR_NAME="{}"'.format(args.libdir_name.strip('/')))
+        cppflags.append('-DFOR_LAUNCHER')
+    cppflags.append('-DLIB_DIR_NAME="{}"'.format(args.libdir_name.strip('/')))
     pylib = get_python_flags(cflags)
     exe = 'kitty-profile' if args.profile else 'kitty'
+    cppflags += shlex.split(os.environ.get('CPPFLAGS', ''))
     cflags += shlex.split(os.environ.get('CFLAGS', ''))
     ldflags = shlex.split(os.environ.get('LDFLAGS', ''))
-    cmd = [env.cc] + cflags + [
+    cmd = [env.cc] + cppflags + cflags + [
         'linux-launcher.c', '-o',
         os.path.join(launcher_dir, exe)
     ] + ldflags + libs + pylib