diff --git a/makefile b/makefile
index 02a7d47..3c170fb 100644
--- a/makefile
+++ b/makefile
@@ -1,6 +1,27 @@
+# DESTDIR envvar is a way to install the application in a different root (for building packages for example).
+PREFIX    ?= /usr/local
+BINDIR    ?= $(PREFIX)/bin
+SHAREDIR  ?= $(PREFIX)/share
+DOCDIR    ?= $(SHAREDIR)/doc/dnsmanagerd
+MANDIR    ?= $(SHAREDIR)/man
+
+CFLAGS ?= -Wall -Wextra
+
 all: build
 
-build:
-	[ -d ./bin ] || mkdir bin
-	cc -o bin/b64-lbl-encode src/b64-lbl-encode.c
-	cc -o bin/b64-lbl-decode src/b64-lbl-decode.c
+install: build
+	$(Q)install -D -m 555 bin/* --target-directory=$(DESTDIR)$(BINDIR)/
+
+build: bin bin/b64-lbl-encode bin/b64-lbl-decode
+
+bin:
+	[ -d bin ] || mkdir bin
+
+bin/b64-lbl-encode: src/b64-lbl-encode.c
+	cc -o bin/b64-lbl-encode src/b64-lbl-encode.c $(CFLAGS)
+
+bin/b64-lbl-decode: src/b64-lbl-decode.c
+	cc -o bin/b64-lbl-decode src/b64-lbl-decode.c $(CFLAGS)
+
+clean:
+	rm bin/*
diff --git a/src/b64-lbl-decode.c b/src/b64-lbl-decode.c
index 31d6eff..b8af880 100644
--- a/src/b64-lbl-decode.c
+++ b/src/b64-lbl-decode.c
@@ -10,7 +10,7 @@ static const char *base64_chars =
     "0123456789+/";
 
 int base64_decode(const char *input, unsigned char *output, size_t *output_length) {
-    int input_length = strlen(input);
+    size_t input_length = strlen(input);
     if (input_length % 4 != 0) return -1; // Base64 input must be a multiple of 4.
     
     // Calculate output length
@@ -18,7 +18,7 @@ int base64_decode(const char *input, unsigned char *output, size_t *output_lengt
     if (input[input_length - 1] == '=') (*output_length)--;
     if (input[input_length - 2] == '=') (*output_length)--;
 
-    for (int i = 0, j = 0; i < input_length; ) {
+    for (size_t i = 0, j = 0; i < input_length; ) {
         unsigned int a = input[i] == '=' ? 0 : strchr(base64_chars, input[i]) - base64_chars; i++;
         unsigned int b = input[i] == '=' ? 0 : strchr(base64_chars, input[i]) - base64_chars; i++;
         unsigned int c = input[i] == '=' ? 0 : strchr(base64_chars, input[i]) - base64_chars; i++;
diff --git a/src/b64-lbl-encode.c b/src/b64-lbl-encode.c
index 9b2337f..59668f2 100644
--- a/src/b64-lbl-encode.c
+++ b/src/b64-lbl-encode.c
@@ -10,7 +10,7 @@ static const char *base64_chars =
     "0123456789+/";
 
 void base64_encode(const unsigned char *input, size_t input_length, char *output, size_t *output_length) {
-    int i, j;
+    size_t i, j;
     *output_length = 4 * ((input_length + 2) / 3); // Calculate output size
 
     for (i = 0, j = 0; i < input_length;) {