Fix typos, especially those that end up in the Nix manual

src/libexpr/eval.cc

@@ -158,7 +158,7 @@ EvalState::EvalState()
            physical RAM, up to a maximum of 384 MiB) so that in most
            cases we don't need to garbage collect at all.  (Collection
            has a fairly significant overhead.)  The heap size can be
-           overriden through libgc's GC_INITIAL_HEAP_SIZE environment
+           overridden through libgc's GC_INITIAL_HEAP_SIZE environment
            variable.  We should probably also provide a nix.conf
            setting for this.  Note that GC_expand_hp() causes a lot of
            virtual, but not physical (resident) memory to be

src/libstore/local-store.cc

@@ -991,7 +991,7 @@ void LocalStore::setSubstituterEnv()
 {
     if (didSetSubstituterEnv) return;
 
-    /* Pass configuration options (including those overriden with
+    /* Pass configuration options (including those overridden with
        --option) to substituters. */
     setenv("_NIX_OPTIONS", settings.pack().c_str(), 1);
 

src/libstore/local-store.hh

@@ -177,7 +177,7 @@ public:
 
     /* Register the validity of a path, i.e., that `path' exists, that
        the paths referenced by it exists, and in the case of an output
-       path of a derivation, that it has been produced by a succesful
+       path of a derivation, that it has been produced by a successful
        execution of the derivation (or something equivalent).  Also
        register the hash of the file system contents of the path.  The
        hash must be a SHA-256 hash. */

src/libutil/serialise.hh

@@ -61,7 +61,7 @@ struct BufferedSource : Source
     
     size_t read(unsigned char * data, size_t len);
     
-    /* Underlying read call, to be overriden. */
+    /* Underlying read call, to be overridden. */
     virtual size_t readUnbuffered(unsigned char * data, size_t len) = 0;
 
     bool hasData();

src/libutil/util.cc

@@ -629,8 +629,8 @@ AutoCloseFD::AutoCloseFD(int fd)
 
 AutoCloseFD::AutoCloseFD(const AutoCloseFD & fd)
 {
-    /* Copying a AutoCloseFD isn't allowed (who should get to close
-       it?).  But as a edge case, allow copying of closed
+    /* Copying an AutoCloseFD isn't allowed (who should get to close
+       it?).  But as an edge case, allow copying of closed
        AutoCloseFDs.  This is necessary due to tiresome reasons
        involving copy constructor use on default object values in STL
        containers (like when you do `map[value]' where value isn't in

src/nix-env/nix-env.cc

@@ -804,7 +804,7 @@ void printTable(Table & table)
 }
 
 
-/* This function compares the version of a element against the
+/* This function compares the version of an element against the
    versions in the given set of elements.  `cvLess' means that only
    lower versions are in the set, `cvEqual' means that at most an
    equal version is in the set, and `cvGreater' means that there is at