Remove three unneeded variable assignments.

Found using Clang's static analyzer.

Python/ceval.c

@@ -2697,7 +2697,6 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
 			    Py_DECREF(*pfunc);
 			    *pfunc = self;
 			    na++;
-			    n++;
 		    } else
 			    Py_INCREF(func);
 		    sp = stack_pointer;

Python/dtoa.c

@@ -1382,7 +1382,6 @@ bigcomp(U *rv, const char *s0, BCinfo *bc)
     Bigint *b, *d;
     int b2, d2, dd, i, nd, nd0, odd, p2, p5;
 
-    dd = 0; /* silence compiler warning about possibly unused variable */
     nd = bc->nd;
     nd0 = bc->nd0;
     p5 = nd + bc->e0;
@@ -2362,7 +2361,7 @@ _Py_dg_dtoa(double dd, int mode, int ndigits,
 
     /* set pointers to NULL, to silence gcc compiler warnings and make
        cleanup easier on error */
-    mlo = mhi = b = S = 0;
+    mlo = mhi = S = 0;
     s0 = 0;
 
     u.d = dd;
@@ -2713,8 +2712,6 @@ _Py_dg_dtoa(double dd, int mode, int ndigits,
      * and for all and pass them and a shift to quorem, so it
      * can do shifts and ors to compute the numerator for q.
      */
-    if ((i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0x1f))
-        i = 32 - i;
 #define iInc 28
     i = dshift(S, s2);
     b2 += i;

Python/getcwd.c

@@ -28,7 +28,7 @@ getcwd(char *buf, int size)
 {
 	char localbuf[MAXPATHLEN+1];
 	char *ret;
-	
+
 	if (size <= 0) {
 		errno = EINVAL;
 		return NULL;
@@ -59,14 +59,13 @@ getcwd(char *buf, int size)
 {
 	FILE *fp;
 	char *p;
-	int sts;
 	if (size <= 0) {
 		errno = EINVAL;
 		return NULL;
 	}
 	if ((fp = popen(PWD_CMD, "r")) == NULL)
 		return NULL;
-	if (fgets(buf, size, fp) == NULL || (sts = pclose(fp)) != 0) {
+	if (fgets(buf, size, fp) == NULL || pclose(fp) != 0) {
 		errno = EACCES; /* Most likely error */
 		return NULL;
 	}

Python/import.c

@@ -19,7 +19,7 @@
 #include <fcntl.h>
 #endif
 #ifdef __cplusplus
-extern "C" { 
+extern "C" {
 #endif
 
 #ifdef MS_WINDOWS
@@ -826,7 +826,7 @@ parse_source_module(const char *pathname, FILE *fp)
 
 	flags.cf_flags = 0;
 
-	mod = PyParser_ASTFromFile(fp, pathname, Py_file_input, 0, 0, &flags, 
+	mod = PyParser_ASTFromFile(fp, pathname, Py_file_input, 0, 0, &flags,
 				   NULL, arena);
 	if (mod) {
 		co = PyAST_Compile(mod, pathname, NULL, arena);
@@ -884,7 +884,7 @@ write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat)
 	mode_t mode = srcstat->st_mode & ~S_IEXEC;
 #else
 	mode_t mode = srcstat->st_mode & ~S_IXUSR & ~S_IXGRP & ~S_IXOTH;
-#endif 
+#endif
 
 	fp = open_exclusive(cpathname, mode);
 	if (fp == NULL) {
@@ -972,7 +972,7 @@ load_source_module(char *name, char *pathname, FILE *fp)
 	char *cpathname;
 	PyCodeObject *co;
 	PyObject *m;
-	
+
 	if (fstat(fileno(fp), &st) != 0) {
 		PyErr_Format(PyExc_RuntimeError,
 			     "unable to get file status from '%s'",
@@ -1406,7 +1406,7 @@ find_module(char *fullname, char *subname, PyObject *path, char *buf,
 			else {
 				char warnstr[MAXPATHLEN+80];
 				sprintf(warnstr, "Not importing directory "
-					"'%.*s': missing __init__.py", 
+					"'%.*s': missing __init__.py",
 					MAXPATHLEN, buf);
 				if (PyErr_Warn(PyExc_ImportWarning,
 					       warnstr)) {
@@ -1427,7 +1427,7 @@ find_module(char *fullname, char *subname, PyObject *path, char *buf,
 			else {
 				char warnstr[MAXPATHLEN+80];
 				sprintf(warnstr, "Not importing directory "
-					"'%.*s': missing __init__.py", 
+					"'%.*s': missing __init__.py",
 					MAXPATHLEN, buf);
 				if (PyErr_Warn(PyExc_ImportWarning,
 					       warnstr)) {
@@ -2266,7 +2266,7 @@ get_parent(PyObject *globals, char *buf, Py_ssize_t *p_buflen, int level)
 		modname = PyDict_GetItem(globals, namestr);
 		if (modname == NULL || !PyString_Check(modname))
 			return Py_None;
-	
+
 		modpath = PyDict_GetItem(globals, pathstr);
 		if (modpath != NULL) {
 			/* __path__ is set, so modname is already the package name */
@@ -2621,7 +2621,7 @@ PyImport_ReloadModule(PyObject *m)
 	struct filedescr *fdp;
 	FILE *fp = NULL;
 	PyObject *newm;
-    
+
 	if (modules_reloading == NULL) {
 		Py_FatalError("PyImport_ReloadModule: "
 			      "no modules_reloading dictionary!");