diff --git a/AK/FileSystemPath.cpp b/AK/FileSystemPath.cpp
index ab00a61c3c4..8c5ffb49325 100644
--- a/AK/FileSystemPath.cpp
+++ b/AK/FileSystemPath.cpp
@@ -14,6 +14,7 @@ FileSystemPath::FileSystemPath(const String& s)
 bool FileSystemPath::canonicalize(bool resolveSymbolicLinks)
 {
     // FIXME: Implement "resolveSymbolicLinks"
+    (void) resolveSymbolicLinks;
     auto parts = m_string.split('/');
     Vector<String> canonicalParts;
 
diff --git a/Kernel/Syscall.h b/Kernel/Syscall.h
index 40f952bdbd8..c680cd0a31b 100644
--- a/Kernel/Syscall.h
+++ b/Kernel/Syscall.h
@@ -88,7 +88,7 @@ struct SC_mmap_params {
     int32_t prot;
     int32_t flags;
     int32_t fd;
-    uint32_t offset; // FIXME: 64-bit off_t?
+    int32_t offset; // FIXME: 64-bit off_t?
 };
 
 void initialize();
diff --git a/LibC/getopt.cpp b/LibC/getopt.cpp
index 76b5e688de5..c7c6afa637c 100644
--- a/LibC/getopt.cpp
+++ b/LibC/getopt.cpp
@@ -91,7 +91,7 @@ int getopt(int nargc, char* const nargv[], const char* ostr)
     }
     else { /* need an argument */
         if (*place) /* no white space */
-            optarg = (char*)place;
+            optarg = const_cast<char*>(place);
         else if (nargc <= ++optind) { /* no arg */
             place = EMSG;
             if (*ostr == ':')
diff --git a/LibC/mntent.cpp b/LibC/mntent.cpp
index 6c57801abaa..792a0f71568 100644
--- a/LibC/mntent.cpp
+++ b/LibC/mntent.cpp
@@ -3,7 +3,7 @@
 
 extern "C" {
 
-struct mntent* getmntent(FILE* stream)
+struct mntent* getmntent(FILE*)
 {
     assert(false);
     return nullptr;
diff --git a/LibC/scanf.cpp b/LibC/scanf.cpp
index b9b4726b7b9..913dbb21eff 100644
--- a/LibC/scanf.cpp
+++ b/LibC/scanf.cpp
@@ -71,7 +71,7 @@ static int _atob(unsigned long* vp, const char* p, int base)
     }
 
     if (base == 16 && (q = strchr(p, '.')) != 0) {
-        if (q - p > sizeof(tmp) - 1)
+        if (q - p > (int)sizeof(tmp) - 1)
             return 0;
         strncpy(tmp, p, q - p);
         tmp[q - p] = '\0';
@@ -164,11 +164,10 @@ static int vfscanf(FILE *fp, const char* fmt, va_list ap)
 
 static int vsscanf(const char *buf, const char *s, va_list ap)
 {
-    int base;
+    int base = 10;
     char *t;
     char tmp[MAXLN];
     bool noassign = false;
-    bool lflag = false;
     int count = 0;
     int width = 0;
 
@@ -182,8 +181,6 @@ static int vsscanf(const char *buf, const char *s, va_list ap)
                     break;
                 if (*s == '*')
                     noassign = true;
-                else if (*s == 'l' || *s == 'L')
-                    lflag = true;
                 else if (*s >= '1' && *s <= '9') {
                     const char* tc;
                     for (tc = s; isdigit(*s); s++);
@@ -238,7 +235,6 @@ static int vsscanf(const char *buf, const char *s, va_list ap)
                 ++count;
             width = 0;
             noassign = false;
-            lflag = false;
             ++s;
         } else {
             while (isspace(*buf))
diff --git a/LibC/stdlib.cpp b/LibC/stdlib.cpp
index 342ab92e2f8..63583ab77ba 100644
--- a/LibC/stdlib.cpp
+++ b/LibC/stdlib.cpp
@@ -49,12 +49,14 @@ void free(void* ptr)
 
 void* calloc(size_t nmemb, size_t)
 {
+    (void) nmemb;
     ASSERT_NOT_REACHED();
     return nullptr;
 }
 
 void* realloc(void *ptr, size_t)
 {
+    (void) ptr;
     ASSERT_NOT_REACHED();
     return nullptr;
 }
@@ -62,6 +64,7 @@ void* realloc(void *ptr, size_t)
 void exit(int status)
 {
     Syscall::invoke(Syscall::SC_exit, (dword)status);
+    for (;;);
 }
 
 void abort()
@@ -91,7 +94,7 @@ char* getenv(const char* name)
 
 int atoi(const char* str)
 {
-    ssize_t len = strlen(str);
+    size_t len = strlen(str);
     int value = 0;
     bool isNegative = false;
     for (size_t i = 0; i < len; ++i) {
diff --git a/LibC/string.cpp b/LibC/string.cpp
index e905248ed0c..e840f28e9d8 100644
--- a/LibC/string.cpp
+++ b/LibC/string.cpp
@@ -119,7 +119,7 @@ char* strchr(const char* str, int c)
     char ch = c;
     for (;; ++str) {
         if (*str == ch)
-            return (char*)str;
+            return const_cast<char*>(str);
         if (!*str)
             return nullptr;
     }
@@ -131,7 +131,7 @@ char* strrchr(const char* str, int ch)
     char c;
     for (; (c = *str); ++str) {
         if (c == ch)
-            last = (char*)str;
+            last = const_cast<char*>(str);
     }
     return last;
 }
@@ -168,18 +168,18 @@ char* strerror(int errnum)
 {
     if (errnum >= __errno_count) {
         printf("strerror() missing string for errnum=%d\n", errnum);
-        return "Unknown error";
+        return const_cast<char*>("Unknown error");
     }
-    return (char*)sys_errlist[errnum];
+    return const_cast<char*>(sys_errlist[errnum]);
 }
 
 char* strsignal(int signum)
 {
     if (signum >= __signal_count) {
         printf("strsignal() missing string for signum=%d\n", signum);
-        return "Unknown signal";
+        return const_cast<char*>("Unknown signal");
     }
-    return (char*)sys_siglist[signum];
+    return const_cast<char*>(sys_siglist[signum]);
 }
 
 }
diff --git a/LibC/time.cpp b/LibC/time.cpp
index b1bee005573..eedac5422c5 100644
--- a/LibC/time.cpp
+++ b/LibC/time.cpp
@@ -10,6 +10,8 @@ time_t time(time_t* tloc)
     struct timezone tz;
     if (gettimeofday(&tv, &tz) < 0)
         return (time_t)-1;
+    if (tloc)
+        *tloc = tv.tv_sec;
     return tv.tv_sec;
 }
 
diff --git a/LibC/time.h b/LibC/time.h
index c1b61b574a4..38a1fb21e89 100644
--- a/LibC/time.h
+++ b/LibC/time.h
@@ -5,7 +5,7 @@
 
 __BEGIN_DECLS
 
-typedef struct timezone {
+struct timezone {
     int tz_minuteswest;
     int tz_dsttime;
 };