4 files changed, 8 insertions, 10 deletions
diff --git a/mesonbuild/envconfig.py b/mesonbuild/envconfig.py
index 9402d38..5258fa0 100644
--- a/mesonbuild/envconfig.py
+++ b/mesonbuild/envconfig.py
@@ -211,13 +211,13 @@ class MachineInfo:
         """
         Machine is windows?
         """
-        return self.system == 'windows' or 'mingw' in self.system
+        return self.system == 'windows'
 
     def is_cygwin(self) -> bool:
         """
         Machine is cygwin?
         """
-        return self.system.startswith('cygwin')
+        return self.system == 'cygwin'
 
     def is_linux(self) -> bool:
         """
diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index f1bd2e1..eb7189c 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -429,10 +429,9 @@ def detect_cpu(compilers: CompilersDict):
     return trial
 
 def detect_system():
-    system = platform.system().lower()
-    if system.startswith('cygwin'):
+    if sys.platform == 'cygwin':
         return 'cygwin'
-    return system
+    return platform.system().lower()
 
 def detect_msys2_arch():
     if 'MSYSTEM_CARCH' in os.environ:
diff --git a/mesonbuild/mesonlib.py b/mesonbuild/mesonlib.py
index 45e3b34..a510ab9 100644
--- a/mesonbuild/mesonlib.py
+++ b/mesonbuild/mesonlib.py
@@ -502,11 +502,11 @@ def is_openbsd() -> bool:
 
 def is_windows() -> bool:
     platname = platform.system().lower()
-    return platname == 'windows' or 'mingw' in platname
+    return platname == 'windows'
 
 
 def is_cygwin() -> bool:
-    return platform.system().lower().startswith('cygwin')
+    return sys.platform == 'cygwin'
 
 
 def is_debianlike() -> bool:
diff --git a/mesonbuild/mtest.py b/mesonbuild/mtest.py
index d7fe54a..de82234 100644
--- a/mesonbuild/mtest.py
+++ b/mesonbuild/mtest.py
@@ -58,11 +58,10 @@ GNU_ERROR_RETURNCODE = 99
 
 def is_windows() -> bool:
     platname = platform.system().lower()
-    return platname == 'windows' or 'mingw' in platname
+    return platname == 'windows'
 
 def is_cygwin() -> bool:
-    platname = platform.system().lower()
-    return 'cygwin' in platname
+    return sys.platform == 'cygwin'
 
 def determine_worker_count() -> int:
     varname = 'MESON_TESTTHREADS'