Add ispunct() to LibC + some minor cleanups.

Kernel/sync.sh

@@ -8,7 +8,6 @@ cp -v ../Userland/sh mnt/bin/sh
 cp -v ../Userland/id mnt/bin/id
 cp -v ../Userland/ps mnt/bin/ps
 cp -v ../Userland/ls mnt/bin/ls
-cp -v ../Userland/pwd mnt/bin/pwd
 cp -v ../Userland/sleep mnt/bin/sleep
 cp -v ../Userland/date mnt/bin/date
 cp -v ../Userland/true mnt/bin/true

LibC/Makefile

@@ -25,6 +25,7 @@ LIBC_OBJS = \
        setjmp.o \
        stat.o \
        mntent.o \
+       ctype.o \
        entry.o
 
 OBJS = $(AK_OBJS) $(LIBC_OBJS)

LibC/ctype.cpp

@@ -0,0 +1,8 @@
+#include <ctype.h>
+#include <string.h>
+
+int ispunct(int c)
+{
+    const char* punctuation_characters = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";
+    return !!strchr(punctuation_characters, c);
+}

LibC/ctype.h

@@ -2,6 +2,8 @@
 
 #include <sys/cdefs.h>
 
+__BEGIN_DECLS
+
 ALWAYS_INLINE int isascii(int ch)
 {
     return (ch & ~0x7f) == 0;
@@ -40,3 +42,7 @@ ALWAYS_INLINE int isdigit(int c)
 {
     return c >= '0' && c <= '9';
 }
+
+int ispunct(int c);
+
+__END_DECLS

LibC/setjmp.cpp

@@ -7,7 +7,7 @@ int setjmp(jmp_buf)
     assert(false);
 }
 
-void longjmp(jmp_buf, int val)
+void longjmp(jmp_buf, int)
 {
     assert(false);
 }