MSYS2: remove support

MSYS2 version was built for smooth transition from POSIX api to Win32 api. It has almost identical output as Windows native version, except requiring msys runtime dll and being a bit slower.

src/detection/terminalshell/terminalshell_linux.c

@@ -28,7 +28,7 @@ static void getProcessInformation(pid_t pid, FFstrbuf* processName, FFstrbuf* ex
     assert(processName->length > 0);
     ffStrbufClear(exe);
 
-    #if defined(__linux__) || defined(__MSYS__)
+    #ifdef __linux__
 
     char cmdlineFilePath[64];
     snprintf(cmdlineFilePath, sizeof(cmdlineFilePath), "/proc/%d/cmdline", (int)pid);
@@ -61,7 +61,7 @@ static const char* getProcessNameAndPpid(pid_t pid, char* name, pid_t* ppid)
 {
     const char* error = NULL;
 
-    #if defined(__linux__) || defined(__MSYS__)
+    #ifdef __linux__
 
     char statFilePath[64];
     snprintf(statFilePath, sizeof(statFilePath), "/proc/%d/stat", (int)pid);