Use POSIX macros for linux

cde/programs/dtsession/SmConMgmt.c

@@ -55,7 +55,7 @@
 
 #include <stdio.h>
 #include <fcntl.h>
-#if !defined(linux)
+#if !defined(__linux__)
 #include <nlist.h>
 #endif
 #include <X11/Intrinsic.h>
@@ -109,7 +109,7 @@ int clientRunning;
 /*
  * Variables global to this module only
  */
-#if !defined(linux)
+#if !defined(__linux__)
 static struct nlist namelist[3];
 #endif
 static int freemem_loc, gpgslim_loc, gpgslim, freemem;
@@ -160,7 +160,7 @@ static void WaitClientTimeout(XtPointer, XtIntervalId *);
 int 
 GetMemoryUtilization(void)
 {
-#if !defined(linux)
+#if !defined(__linux__)
     static int init = 0;
     static int kmem;
 #if !defined(SVR4) && !defined(hpV4) && !defined(_POWER) && !defined(CSRG_BASED)

cde/programs/dtsession/SmLock.c

@@ -77,7 +77,7 @@
 #  include <shadow.h>
 #endif
 
-#if defined(linux)
+#if defined(__linux__)
 # include <shadow.h>
 #endif
 #if defined(CSRG_BASED)
@@ -144,7 +144,7 @@ static void RequirePassword( XtPointer, XtIntervalId *) ;
 static void CycleSaver( XtPointer, XtIntervalId *) ;
 static void BlinkCaret( XtPointer, XtIntervalId *) ;
 
-#if defined(linux)
+#if defined(__linux__)
 /* #define JET_AUTHDEBUG */
 
 /* Test for re-auth ability - see if we can re-authenticate via pwd,
@@ -1661,7 +1661,7 @@ localAuthenticate(
       return FALSE;
 }
     
-#elif defined(linux)
+#elif defined(__linux__)
 
 {
     struct passwd *pwent = NULL;