patch 8.1.0662: needlessly searching for tilde in string

Problem:    Needlessly searching for tilde in string.
Solution:   Only check the first character. (James McCoy, closes #3734)
diff --git a/src/misc1.c b/src/misc1.c
index 40d6f93..a552751 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -4924,7 +4924,7 @@
 	homedir_env = NULL;
 
 #if defined(FEAT_MODIFY_FNAME) || defined(FEAT_EVAL)
-    if (homedir_env != NULL && vim_strchr(homedir_env, '~') != NULL)
+    if (homedir_env != NULL && *homedir_env == '~')
     {
 	int	usedlen = 0;
 	int	flen;
diff --git a/src/version.c b/src/version.c
index c49e869..c2869ce 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    662,
+/**/
     661,
 /**/
     660,