Finally hook up the mkdir code to a syscall.

Added a /bin/mkdir that makes directories. How very neat :^)
There are various limitations because of missing functionality.

Userland/.gitignore

@@ -20,3 +20,4 @@ ft
 ft2
 strsignal
 fgrep
+mkdir

Userland/Makefile

@@ -18,7 +18,8 @@ OBJS = \
        ft2.o \
        strsignal.o \
        fgrep.o \
-       tty.o
+       tty.o \
+       mkdir.o
 
 APPS = \
        id \
@@ -40,7 +41,8 @@ APPS = \
        ft2 \
        strsignal \
        fgrep \
-       tty
+       tty \
+       mkdir
 
 ARCH_FLAGS =
 STANDARD_FLAGS = -std=c++17 -nostdinc++ -nostdlib -nostdinc
@@ -120,6 +122,9 @@ tty: tty.o
 strsignal: strsignal.o
 	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
 
+mkdir: mkdir.o
+	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
+
 .cpp.o:
 	@echo "CXX $<"; $(CXX) $(CXXFLAGS) -o $@ -c $<
 

Userland/mkdir.cpp

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <sys/stat.h>
+
+int main(int argc, char** argv)
+{
+    if (argc != 2) {
+        printf("usage: mkdir <path>\n");
+        return 1;
+    }
+    int rc = mkdir(argv[1], 0755);
+    if (rc < 0) {
+        perror("mkdir");
+        return 1;
+    }
+    return 0;
+}