diff --git a/agrep.c b/agrep.c
index 765eeb5..92efcd4 100644
--- a/agrep.c
+++ b/agrep.c
@@ -222,6 +222,7 @@ CHAR *agrep_saved_pattern = NULL;	/* to prevent multiple prepfs for each boolean
 #ifdef _WIN32
 #include <direct.h>
 #include <io.h>
+#endif
 int  agrep_usage();       /* agrep.c */
 int  exec();              /* agrep.c */
 int  exponen();           /* agrep.c */
@@ -244,7 +245,6 @@ int  sgrep();             /* sgrep.c */
 int  initialize_common(); /* dummyfil.c */
 int  tuncompressible_filename();   /* dummyfil.c */
 int  quick_tcompress();   /* dummyfil.c */
-#endif
 
 /* Called when multipattern search and pattern has not changed */
 
diff --git a/agrephlp.c b/agrephlp.c
index d3df89c..98185ca 100644
--- a/agrephlp.c
+++ b/agrephlp.c
@@ -10,8 +10,8 @@
 
 #ifdef _WIN32
 #include "conio.h"
-int get_current_codepage();  /* codepage.c */
 #endif
+int get_current_codepage();  /* codepage.c */
 
 #define	CUL	0x4B00
 #define CUP	0x4800
@@ -65,8 +65,8 @@ int get_current_codepage();  /* codepage.c */
 #include "agrep.h"
 #include "version.h"
 
-extern	AGREPOPT_STR[MAX_LINE_LEN];
-extern	VERBOSE;
+extern char AGREPOPT_STR[MAX_LINE_LEN];
+extern int VERBOSE;
 
 #ifdef __EMX__
 extern	unsigned int _emx_env;
diff --git a/asearch.c b/asearch.c
index 5a57e11..574f301 100644
--- a/asearch.c
+++ b/asearch.c
@@ -23,11 +23,9 @@ extern int NEW_FILE, POST_FILTER;
 
 extern int LIMITOUTPUT, LIMITPERFILE;
 
-#ifdef _WIN32
 int  output();            /* agrep.c */
 int  asearch0();          /* asearch.c */
 int  fill_buf();          /* bitap.c */
-#endif
 
 int
 asearch(old_D_pat, text, D)
diff --git a/asearch1.c b/asearch1.c
index c577d70..50af21e 100644
--- a/asearch1.c
+++ b/asearch1.c
@@ -20,10 +20,8 @@ extern int NEW_FILE, POST_FILTER;
 
 extern int LIMITOUTPUT, LIMITPERFILE;
 
-#ifdef _WIN32
 int  output();            /* agrep.c */
 int  fill_buf();          /* bitap.c */
-#endif
 
 int
 asearch1(old_D_pat, Text, D)
diff --git a/bitap.c b/bitap.c
index 2afa1d5..4942f37 100644
--- a/bitap.c
+++ b/bitap.c
@@ -65,13 +65,13 @@ extern int NEW_FILE, POST_FILTER;
 
 #ifdef _WIN32
 #include <io.h>
+#endif
 int  output();            /* agrep.c */
 int  re();                /* agrep.c */
 int  re1();               /* agrep.c */
 int  asearch();           /* asearch.c */
 int  asearch1();          /* asearch1.c */
 int  fill_buf();          /* bitap.c */
-#endif
 
 /* bitap dispatches job */
 
@@ -447,6 +447,7 @@ int fd, M, D;
 #endif	/*AGREP_POINTER*/
 }
 
+int
 fill_buf(fd, buf, record_size)
 int fd, record_size; 
 unsigned char *buf;
diff --git a/codepage.c b/codepage.c
index b448b7b..7b0d4a5 100644
--- a/codepage.c
+++ b/codepage.c
@@ -47,7 +47,7 @@ char	CP_MAPPING;			/* -i option = case(in)sensitive search ?
 unsigned char LUT[256];			/* THE LOOK-UP TABLE (filled in AGREP.C) */
 
 
-int get_current_codepage(VOID)
+int get_current_codepage(void)
 
 #ifdef __EMX__
 
diff --git a/compat.c b/compat.c
index 7635bf7..e50fbeb 100644
--- a/compat.c
+++ b/compat.c
@@ -8,13 +8,13 @@
 
 extern int D;
 extern int FILENAMEONLY, APPROX, PAT_FILE, PAT_BUFFER, MULTI_OUTPUT, COUNT, INVERSE, BESTMATCH;
-extern FILEOUT;
-extern REGEX;
-extern DELIMITER;
-extern WHOLELINE;
-extern LINENUM;
-extern I, S, DD;
-extern JUMP;
+extern int FILEOUT;
+extern int REGEX;
+extern int DELIMITER;
+extern int WHOLELINE;
+extern int LINENUM;
+extern int I, S, DD;
+extern int JUMP;
 extern char Progname[32];
 extern int agrep_initialfd;
 extern int EXITONERROR;
diff --git a/main.c b/main.c
index 81ec0f2..1acd1e2 100644
--- a/main.c
+++ b/main.c
@@ -20,9 +20,7 @@ extern  int EXITONERROR;
 extern unsigned int _emx_env;	/* this variable denotes the operating system DOS, OS/2 */
 #endif
 
-#ifdef _WIN32
 int fileagrep();   /* agrep.c */
-#endif
 
 #ifndef _WIN32
 int
diff --git a/maskgen.c b/maskgen.c
index e8e28e9..1348671 100644
--- a/maskgen.c
+++ b/maskgen.c
@@ -16,7 +16,7 @@ extern int CODEPAGE;
 extern struct CODEPAGE_struct CP[CODEPAGES][CPSIZE];
 
 extern unsigned D_endpos, endposition, Init1, wildmask;
-extern Mask[], Bit[], Init[], NO_ERR_MASK;
+extern unsigned Mask[], Bit[], Init[], NO_ERR_MASK;
 extern int AND, REGEX, NOUPPER, D_length;
 extern unsigned char Progname[];
 extern int agrep_initialfd;
diff --git a/newmgrep.c b/newmgrep.c
index bff5748..20d343c 100644
--- a/newmgrep.c
+++ b/newmgrep.c
@@ -70,14 +70,14 @@ extern CHAR D_pattern[MaxDelimit*2];
 extern int D_length;
 extern CHAR tc_D_pattern[MaxDelimit*2];
 extern int tc_D_length;
-extern COUNT, FNAME, SILENT, FILENAMEONLY, prev_num_of_matched, num_of_matched;
-extern INVERSE, OUTTAIL;
-extern WORDBOUND, WHOLELINE, NOUPPER;
+extern int COUNT, FNAME, SILENT, FILENAMEONLY, prev_num_of_matched, num_of_matched;
+extern int INVERSE, OUTTAIL;
+extern int WORDBOUND, WHOLELINE, NOUPPER;
 extern ParseTree *AParse;
 extern int AComplexPattern;
 extern unsigned char  CurrentFileName[], Progname[]; 
-extern total_line;
-extern agrep_initialfd;
+extern int total_line;
+extern int agrep_initialfd;
 extern int EXITONERROR;
 extern int PRINTPATTERN;
 extern int agrep_inlen;
@@ -119,12 +119,10 @@ extern int anum_terminals;
 extern int AComplexBoolean;
 static void countline(unsigned char *text, int len);
 
-#ifdef _WIN32
 int  eval_tree();         /* asplit.c */
 int  fill_buf();          /* bitap.c */
 int  monkey1();           /* newmgrep.c */
 int  m_short();           /* newmgrep.c */
-#endif
 
 #if	DOTCOMPRESSED
 /* Equivalent variables for compression search */
diff --git a/parse.c b/parse.c
index ecb1bc2..3d20b41 100644
--- a/parse.c
+++ b/parse.c
@@ -6,10 +6,10 @@
 
 #ifdef _WIN32
 #include <memory.h>
-#include <stdlib.h>
 #endif
 
 #include <stdio.h>
+#include <stdlib.h>
 #include "re.h"
 
 #define FALSE	0
diff --git a/preproce.c b/preproce.c
index 904b285..794ce4a 100644
--- a/preproce.c
+++ b/preproce.c
@@ -42,13 +42,11 @@ extern ParseTree aterminals[MAXNUM_PAT];
 extern char FREQ_FILE[MAX_LINE_LEN], HASH_FILE[MAX_LINE_LEN], STRING_FILE[MAX_LINE_LEN];	/* interfacing with tcompress */
 extern int AComplexBoolean;
 
-#ifdef _WIN32
 int  asplit_pattern();       /* asplit.c */
 int  asplit_terminal();      /* asplit.c */
 int  init();                 /* follow.c */
 void destroy_tree();         /* putils.c */
 int  quick_tcompress();      /* preproce.c */
-#endif
 
 int
 preprocess(D_pattern, Pattern)   /* need two parameters  */
diff --git a/putils.c b/putils.c
index adc8ea2..1677ac0 100644
--- a/putils.c
+++ b/putils.c
@@ -68,6 +68,7 @@ get_token_bool(buffer, len, ptr, tokenbuf, tokenlen)
 void
 print_tree(t, level)
 	ParseTree *t;
+	int level;
 {
 	int	i;
 
diff --git a/re.h b/re.h
index 8d18f34..ba3df38 100644
--- a/re.h
+++ b/re.h
@@ -4,6 +4,9 @@
 					allows the fully ISO-Charset.
 */
 
+#include <stdlib.h>
+#include <string.h>
+
 /*************************************************************
  *							     *
  * 	Macros defining special characters.		     *
@@ -72,8 +75,6 @@
 
 #define new_node(type, l, x)	\
 {\
-	extern void *malloc();\
-\
 	(l) = (type) malloc(sizeof(*(x)));\
 	if ((l) == NULL) {\
 		fprintf(stderr, "malloc failure in new_node\n");\
diff --git a/recursiv.c b/recursiv.c
index 0d1d520..df4fc0d 100644
--- a/recursiv.c
+++ b/recursiv.c
@@ -21,6 +21,8 @@
 
 #include "autoconf.h"	/* ../libtemplate/include */
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <sys/types.h>
 
 #if	ISO_CHAR_SET
@@ -59,12 +61,10 @@
 
 #ifdef _WIN32
 #include "config.h"
-#include <string.h>
 #include <malloc.h>
-#include <sys/types.h>
 #include <sys/stat.h>
-int  exec();    /* agrep.c */
 #endif
+int  exec();    /* agrep.c */
 
 /*
  * #include <sys/stat.h>
diff --git a/sgrep.c b/sgrep.c
index 9dce86c..374aa3a 100644
--- a/sgrep.c
+++ b/sgrep.c
@@ -97,7 +97,7 @@ extern int CONSTANT, COUNT, FNAME, SILENT, FILENAMEONLY, prev_num_of_matched, nu
 extern int DNA ;	/* DNA flag is set in checksg when pattern is DNA pattern
 			   and p_size > 16  */
 
-extern WORDBOUND, WHOLELINE, NOUPPER;
+extern int WORDBOUND, WHOLELINE, NOUPPER;
 extern unsigned char CurrentFileName[],  Progname[]; 
 extern unsigned Mask[];
 extern unsigned endposition;
@@ -123,7 +123,6 @@ extern void free_buf(int fd, char *sbuf);
 extern unsigned char * backward_delimiter(unsigned char *end, unsigned char *begin, unsigned char *delim, int len, int outtail);
 extern unsigned char * forward_delimiter(unsigned char *begin, unsigned char *end, unsigned char *delim, int len, int outtail);
 
-#ifdef _WIN32
 int  fill_buf();          /* bitap.c */
 int  a_monkey();          /* sgrep.c */
 int  agrep();             /* sgrep.c */
@@ -133,7 +132,6 @@ int  monkey();            /* sgrep.c */
 int  monkey4();           /* sgrep.c */
 int  s_output();          /* sgrep.c */
 int  verify();            /* sgrep.c */
-#endif
 
 #if	MEASURE_TIMES
 /* timing variables */
@@ -262,7 +260,7 @@ int *m;
 int sgrep(in_pat, in_m, fd, D, samepattern)
 
 CHARTYPE *in_pat;  
-int fd, in_m, D;
+int fd, in_m, D, samepattern;
 {
 	CHARTYPE patbuf[MAXLINE];
 	CHARTYPE *pat = patbuf;
@@ -1485,7 +1483,7 @@ CHARTYPE **lastout;	/* in, out */
 static void
 prep_bm(Pattern, m)      
 unsigned char *Pattern;
-register m;
+register int m;
 {
 	int i;
 	unsigned hash;
diff --git a/utilitie.c b/utilitie.c
index 57021e3..a62088a 100644
--- a/utilitie.c
+++ b/utilitie.c
@@ -2,14 +2,15 @@
 /* this file contains various utility functions for accessing
    and manipulating regular expression syntax trees.	*/
 
-#include <stdio.h>
 #include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include "re.h"
 
 #ifdef _WIN32
 #include <malloc.h>
 #include <process.h>
-#include <string.h>
 #endif
 
 /************************************************************************/