diff --git a/icu4c/source/common/cmemory.c b/icu4c/source/common/cmemory.c
index 45902dc9557..0f93f36a63d 100644
--- a/icu4c/source/common/cmemory.c
+++ b/icu4c/source/common/cmemory.c
@@ -18,8 +18,9 @@
 *
 ******************************************************************************
 */
-#include "cmemory.h"
 #include "unicode/uclean.h"
+#include "cmemory.h"
+#include <stdlib.h>
 
 /* uprv_malloc(0) returns a pointer to this read-only data. */                
 static const int32_t zeroMem[] = {0, 0, 0, 0, 0, 0};
diff --git a/icu4c/source/common/cmemory.h b/icu4c/source/common/cmemory.h
index ffcfa2dbd9b..da65d7cebf4 100644
--- a/icu4c/source/common/cmemory.h
+++ b/icu4c/source/common/cmemory.h
@@ -25,7 +25,6 @@
 #define CMEMORY_H
 
 #include "unicode/utypes.h"
-#include <stdlib.h>
 #include <string.h>
 
 
diff --git a/icu4c/source/test/cintltst/cintltst.h b/icu4c/source/test/cintltst/cintltst.h
index 199496e0d3c..23f5a47b051 100644
--- a/icu4c/source/test/cintltst/cintltst.h
+++ b/icu4c/source/test/cintltst/cintltst.h
@@ -22,6 +22,7 @@ The main root for C API tests
 #include "unicode/utypes.h"
 #include "unicode/putil.h"
 #include "unicode/ctest.h"
+#include <stdlib.h>
 
 #ifndef U_USE_DEPRECATED_API
 #define U_USE_DEPRECATED_API 1
diff --git a/icu4c/source/test/cintltst/creststn.c b/icu4c/source/test/cintltst/creststn.c
index 6a3eaca19bd..3bbefcada1f 100644
--- a/icu4c/source/test/cintltst/creststn.c
+++ b/icu4c/source/test/cintltst/creststn.c
@@ -2110,7 +2110,7 @@ static void TestResourceLevelAliasing(void) {
       
       if(U_FAILURE(status)) {
         log_err("%s trying to read binary BreakDictionaryData\n");
-      } else if(binSeqLen != binLen || uprv_memcmp(binSequence, binary, binSeqLen) != 0) {
+      } else if(binSeqLen != binLen || memcmp(binSequence, binary, binSeqLen) != 0) {
         log_err("Referencing alias didn't get the right data\n");
       }
       
diff --git a/icu4c/source/test/intltest/apicoll.cpp b/icu4c/source/test/intltest/apicoll.cpp
index ceae01a0ffc..eb340a71c27 100644
--- a/icu4c/source/test/intltest/apicoll.cpp
+++ b/icu4c/source/test/intltest/apicoll.cpp
@@ -42,6 +42,7 @@
 
 #include "sfwdchit.h"
 #include "cmemory.h"
+#include <stdlib.h>
 
 void
 CollationAPITest::doAssert(UBool condition, const char *message)
diff --git a/icu4c/source/tools/genrb/parse.c b/icu4c/source/tools/genrb/parse.c
index 786bf67a477..3312f6ada7e 100644
--- a/icu4c/source/tools/genrb/parse.c
+++ b/icu4c/source/tools/genrb/parse.c
@@ -30,6 +30,7 @@
 #include "reslist.h"
 #include "unicode/ustring.h"
 #include "unicode/putil.h"
+#include <stdio.h>
 
 /* Number of tokens to read ahead of the current stream position */
 #define MAX_LOOKAHEAD   3
diff --git a/icu4c/source/tools/toolutil/ucbuf.h b/icu4c/source/tools/toolutil/ucbuf.h
index 069cd1a4893..e0ef18661a6 100644
--- a/icu4c/source/tools/toolutil/ucbuf.h
+++ b/icu4c/source/tools/toolutil/ucbuf.h
@@ -17,11 +17,8 @@
 *******************************************************************************
 */
 
-#include "unicode/utypes.h"
 #include "unicode/ucnv.h"
 #include "filestrm.h"
-#include "cmemory.h"
-#include <stdio.h>
 
 #ifndef UCBUF_H
 #define UCBUF_H 1
diff --git a/icu4c/source/tools/toolutil/uperf.cpp b/icu4c/source/tools/toolutil/uperf.cpp
index 3493ae29d7f..10feb45f422 100644
--- a/icu4c/source/tools/toolutil/uperf.cpp
+++ b/icu4c/source/tools/toolutil/uperf.cpp
@@ -5,6 +5,9 @@
  ********************************************************************/
 
 #include "uperf.h"
+#include "cmemory.h"
+#include <stdio.h>
+#include <stdlib.h>
 
 static const char delim = '/';
 static int32_t execCount = 0;