diff --git a/README.md b/README.md
index d9aa711..b6bc439 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # README #
 
-µEMACS (ue) on Cygwin/Linux/NetBSD, based on uEmacs/PK (em) from [kernel.org](
-https://git.kernel.org/pub/scm/editors/uemacs/uemacs.git/).
+µEMACS (ue) on Cygwin/MSYS2/Linux/NetBSD/OpenBSD, based on uEmacs/PK (em)
+from [kernel.org](https://git.kernel.org/pub/scm/editors/uemacs/uemacs.git/).
 
 ### Changes compare to uEmacs/PK ###
 
@@ -26,6 +26,6 @@ https://git.kernel.org/pub/scm/editors/uemacs/uemacs.git/).
 
 ### How to build ###
 
-* dependencies: gcc, gmake, ncurses-devel.
+* dependencies: (gcc || clang) && gmake && ncurses-devel.
 
 * make
diff --git a/defines.h b/defines.h
index 1b328a4..c222c75 100644
--- a/defines.h
+++ b/defines.h
@@ -2,9 +2,9 @@
 #ifndef __DEFINES_H__
 #define __DEFINES_H__
 
-#if __unix__
+#if __unix__ || (defined(__APPLE__) && defined(__MACH__))
 # define UNIX 1
-# if __NetBSD__
+# if __NetBSD__ || __OpenBSD__ || (defined(__APPLE__) && defined(__MACH__))
 #  define BSD 1
 #  define POSIX 1
 # elif __linux__
diff --git a/exec.c b/exec.c
index b6577d4..c8bf6cc 100644
--- a/exec.c
+++ b/exec.c
@@ -557,9 +557,7 @@ static int dobuf( buffer_p bp) {
 	/* remove leading spaces */
 		if( eline != lp->l_text) {
 			int size = lp->l_used = eol - eline ;
-			if( size)
-				memcpy( lp->l_text, eline, size) ;
-
+			memmove( lp->l_text, eline, size) ;
 			eline = lp->l_text ;
 			eol = &lp->l_text[ size] ;
 		}
@@ -595,7 +593,7 @@ static int dobuf( buffer_p bp) {
 		/* turn line into a string */
 			int size = lp->l_used - 6 ;
 			if( size)
-				memcpy( lp->l_text, &eline[ 6], size) ;
+				memmove( lp->l_text, &eline[ 6], size) ;
 
 			eline = lp->l_text ;
 			eline[ size] = 0 ;
diff --git a/line.c b/line.c
index 593a87b..f91a3b6 100644
--- a/line.c
+++ b/line.c
@@ -293,7 +293,7 @@ boolean linstr( char *instr) {
 boolean linsert_byte( int n, int c) {
     char *cp1;
     char *cp2;
-    line_p lp2, lp3 ;
+    line_p lp2 ;
 	int i ;
 
     assert( (curbp->b_mode & MDVIEW) == 0) ;
@@ -308,16 +308,34 @@ boolean linsert_byte( int n, int c) {
         if( lp2 == NULL)
             return FALSE ;
 
-        lp3 = lp1->l_bp ;	/* Previous line        */
-        lp3->l_fp = lp2 ;	/* Link in              */
+	/* Insert after previous line */
+        lp1->l_bp->l_fp = lp2 ;
         lp2->l_fp = lp1 ;
+        lp2->l_bp = lp1->l_bp ;
         lp1->l_bp = lp2 ;
-        lp2->l_bp = lp3 ;
         for( i = 0 ; i < n ; ++i)
             lp2->l_text[ i] = c ;
 
+	/* update point of current window */
         curwp->w_dotp = lp2 ;
         curwp->w_doto = n ;
+
+	/* update all windows displaying current buffer */
+		for( window_p wp = wheadp ; wp != NULL ; wp = wp->w_wndp)
+			if( wp->w_bufp == curbp) {
+			/* update top window line */
+				if( wp->w_linep == lp1)
+					wp->w_linep = lp2 ;
+
+			/* dot at end of buffer is now at beginning of new line */
+				if( wp->w_dotp == lp1)
+					wp->w_dotp = lp2 ;
+
+			/* mark at end of buffer is now at beginning of new line */
+				if( wp->w_markp == lp1)
+					wp->w_markp = lp2 ;
+			}
+
         return TRUE ;
     }
 
@@ -455,29 +473,30 @@ boolean lnewline( void) {
 
     memcpy( lp2->l_text, lp1->l_text, doto) ;
     lp1->l_used -= doto ;
-	memcpy( lp1->l_text, &lp1->l_text[ doto], lp1->l_used) ;
+	memmove( lp1->l_text, &lp1->l_text[ doto], lp1->l_used) ;
     lp2->l_fp = lp1 ;
     lp2->l_bp = lp1->l_bp ;
     lp1->l_bp = lp2 ;
     lp2->l_bp->l_fp = lp2 ;
-    for( window_p wp = wheadp ; wp != NULL ; wp = wp->w_wndp) {
-        if( wp->w_linep == lp1)
-            wp->w_linep = lp2 ;
+    for( window_p wp = wheadp ; wp != NULL ; wp = wp->w_wndp)
+		if( wp->w_bufp == curbp) {
+	        if( wp->w_linep == lp1)
+    	        wp->w_linep = lp2 ;
 
-        if( wp->w_dotp == lp1) {
-            if( wp->w_doto < doto)
-                wp->w_dotp = lp2 ;
-            else
-                wp->w_doto -= doto ;
-        }
+			if( wp->w_dotp == lp1) {
+            	if( wp == curwp || wp->w_doto > doto)
+	                wp->w_doto -= doto ;
+				else
+                	wp->w_dotp = lp2 ;
+    	    }
 
-        if (wp->w_markp == lp1) {
-            if( wp->w_marko < doto)
-                wp->w_markp = lp2 ;
-            else
-                wp->w_marko -= doto ;
-        }
-    }
+   	    	if( wp->w_markp == lp1) {
+       	    	if( wp->w_marko > doto)
+   	            	wp->w_marko -= doto ;
+            	else
+           	    	wp->w_markp = lp2 ;
+       		}
+		}
 
     return TRUE ;
 }
diff --git a/main.c b/main.c
index 413dad1..dc3344f 100644
--- a/main.c
+++ b/main.c
@@ -69,6 +69,7 @@
 #include "defines.h"	/* OS specific customization */
 #if UNIX
 # include <signal.h>
+# include <unistd.h>
 #endif
 
 #include "basic.h"
diff --git a/pklock.c b/pklock.c
index 3354946..f86afec 100644
--- a/pklock.c
+++ b/pklock.c
@@ -12,11 +12,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <fcntl.h>
-#ifdef SVR4
 #include <string.h>
-#else
-#include <strings.h>
-#endif
 #include <errno.h>
 
 #include "util.h"
diff --git a/posix.c b/posix.c
index fdf649d..8182920 100644
--- a/posix.c
+++ b/posix.c
@@ -31,8 +31,12 @@ int ttcol = -1 ;		/* Column location of HW cursor */
 
 /* Define missing macroes for BSD and CYGWIN environment */
 #if BSD
-#define OLCUC 0000002
-#define XCASE 0000004
+# ifndef OLCUC
+#  define OLCUC 0000002
+# endif
+# ifndef XCASE
+#  define XCASE 0000004
+# endif
 #endif
 
 #ifdef __CYGWIN__			/* gcc predefined (see cpp -dM) */