diff --git a/Android.mk b/Android.mk
index 8daa508d..06418196 100644
--- a/Android.mk
+++ b/Android.mk
@@ -50,7 +50,7 @@ LOCAL_SRC_FILES := \
     src/utils/utils.c \
 
 LOCAL_CFLAGS := -Wall -DANDROID -DHAVE_MALLOC_H -DHAVE_PTHREAD \
-                -DNOT_HAVE_LOG2 -DWEBP_USE_THREAD \
+                -DWEBP_USE_THREAD \
                 -finline-functions -frename-registers -ffast-math \
                 -s -fomit-frame-pointer -Isrc/webp
 
diff --git a/Makefile.vc b/Makefile.vc
index c69b62dc..c7447d83 100644
--- a/Makefile.vc
+++ b/Makefile.vc
@@ -27,7 +27,7 @@ CCNODBG    = cl.exe /nologo /O2 /DNDEBUG
 CCDEBUG    = cl.exe /nologo /Od /Gm /Zi /D_DEBUG /RTC1
 CFLAGS     = /Isrc /nologo /W3 /EHsc /FD /c /GS
 CFLAGS     = $(CFLAGS) /DWIN32 /D_CRT_SECURE_NO_WARNINGS /DWIN32_LEAN_AND_MEAN
-CFLAGS     = $(CFLAGS) /DHAVE_WINCODEC_H /DWEBP_USE_THREAD /DNOT_HAVE_LOG2
+CFLAGS     = $(CFLAGS) /DHAVE_WINCODEC_H /DWEBP_USE_THREAD
 LDFLAGS    = /LARGEADDRESSAWARE /MANIFEST /NXCOMPAT /DYNAMICBASE
 LDFLAGS    = $(LDFLAGS) $(PLATFORM_LDFLAGS)
 LNKDLL     = link.exe /DLL
diff --git a/configure.ac b/configure.ac
index 09559681..932b4f30 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,11 +29,6 @@ AC_DEFUN([WITHLIB_OPTION],
                               [use $2 libraries from DIR]),
                [$2_LIBS="-L$withval"])])
 
-dnl === Check for native log2
-AC_SEARCH_LIBS([log2], [m],,
-               [AC_DEFINE([NOT_HAVE_LOG2], [1],
-                          [Undefine this if you have log2().])])
-
 dnl === Check for pthread support
 AC_ARG_ENABLE([threading],
               AS_HELP_STRING([--disable-threading],