Use POSIX macros for linux

cde/lib/DtSvc/DtUtil2/EnvControl.c

@@ -426,7 +426,7 @@ _DtEnvControl(
 			if ((ptr = strstr(tempString, "/usr/openwin/bin")))
 #elif defined(CSRG_BASED)
 			if ((ptr = strstr(tempString, "/usr/X11R6/bin")))
-#elif defined(linux)
+#elif defined(__linux__)
 			if ((ptr = strstr(tempString, "/usr/bin")))
 #else
 			if ((ptr = strstr(tempString, "/usr/bin/X11")))
@@ -821,7 +821,7 @@ static void _EnvAdd
 {
   _DtSvcProcessLock();
   if (envBitVector & bv_flag) {
-#if defined(CSRG_BASED) || defined(linux)
+#if defined(CSRG_BASED) || defined(__linux__)
       setenv(envVar, envVarSetting + strlen(envVar) + 1, 1);
 #else
 
@@ -928,7 +928,7 @@ _DtEnvRemove(
                       && ( p[len] == '=' )
                       && !strncmp(p, str, len))
 		{
-#if defined(linux) || defined(CSRG_BASED)
+#if defined(__linux__) || defined(CSRG_BASED)
 		  /* JET - 2/19/99
 		     It seems much safer to let libc worry about this
 		     rather than try to do it ourselves.  

cde/lib/DtSvc/DtUtil2/XlationSvc.c

@@ -49,7 +49,7 @@ $END$
 #include <sys/param.h>        /* MAXPATHLEN */
 
 /* for RADIXCHAR and nl_langinfo */
-#if defined(linux)
+#if defined(__linux__)
 # define RADIXCHAR MON_DECIMAL_POINT
 #endif
 #include <langinfo.h>       
@@ -2199,7 +2199,7 @@ int _DtXlateGetXlateEnv(
    /* then look up version number of execution host */
    if (ret_AppExecEnvVersion) 
    {
-#if defined(sun) || defined(_AIX) || defined(linux) || defined(CSRG_BASED)
+#if defined(sun) || defined(_AIX) || defined(__linux__) || defined(CSRG_BASED)
       char version[SYS_NMLN+SYS_NMLN+2];
 #else
       char version[UTSLEN+UTSLEN+2];
@@ -2252,7 +2252,7 @@ int _DtXlateGetXlateEnv(
 #error OSMAJORVERSION and/or OSMINORVERSION not defined
 #endif
 
-#if defined(linux) || defined(CSRG_BASED)
+#if defined(__linux__) || defined(CSRG_BASED)
       sprintf(buf,"%s%s%s", STR(OSMAJORVERSION), 
                      nl_langinfo('.'), STR(OSMINORVERSION));
 #else