diff --git a/scons/gallium.py b/scons/gallium.py
index 9381f804a31..b216304170f 100755
--- a/scons/gallium.py
+++ b/scons/gallium.py
@@ -237,6 +237,9 @@ def generate(env):
     hosthost_platform = host_platform.system().lower()
     if hosthost_platform.startswith('cygwin'):
         hosthost_platform = 'cygwin'
+    # Avoid spurious crosscompilation in MSYS2 environment.
+    if hosthost_platform.startswith('mingw'):
+        hosthost_platform = 'windows'
     host_machine = os.environ.get('PROCESSOR_ARCHITEW6432', os.environ.get('PROCESSOR_ARCHITECTURE', host_platform.machine()))
     host_machine = {
         'x86': 'x86',
diff --git a/scons/llvm.py b/scons/llvm.py
index 33505f79447..fc128ab1e68 100644
--- a/scons/llvm.py
+++ b/scons/llvm.py
@@ -30,6 +30,7 @@ Tool-specific initialization for LLVM
 import os
 import os.path
 import re
+import platform as host_platform
 import sys
 import distutils.version
 
@@ -192,6 +193,12 @@ def generate(env):
             'uuid',
         ])
 
+        # Mingw-w64 zlib is required when building with LLVM support in MSYS2 environment
+        if host_platform.system().lower().startswith('mingw'):
+            env.Append(LIBS = [
+                 'z',
+            ])
+
         if env['msvc']:
             # Some of the LLVM C headers use the inline keyword without
             # defining it.
diff --git a/src/gallium/drivers/swr/SConscript b/src/gallium/drivers/swr/SConscript
index 61432a0c342..1230cbb5b77 100644
--- a/src/gallium/drivers/swr/SConscript
+++ b/src/gallium/drivers/swr/SConscript
@@ -214,7 +214,7 @@ env.Prepend(CPPPATH = [
 envavx = env.Clone()
 
 envavx.Append(CPPDEFINES = ['KNOB_ARCH=KNOB_ARCH_AVX'])
-if env['platform'] == 'windows':
+if env['msvc']:
     envavx.Append(CCFLAGS = ['/arch:AVX'])
 else:
     envavx.Append(CCFLAGS = ['-mavx'])
@@ -230,7 +230,7 @@ env.Alias('swrAVX', swrAVX)
 envavx2 = env.Clone()
 
 envavx2.Append(CPPDEFINES = ['KNOB_ARCH=KNOB_ARCH_AVX2'])
-if env['platform'] == 'windows':
+if env['msvc']:
     envavx2.Append(CCFLAGS = ['/arch:AVX2'])
 else:
     envavx2.Append(CCFLAGS = ['-mavx2', '-mfma', '-mbmi2', '-mf16c'])