Pin manifest of ndk-release-r21

Change-Id: I2825ce6e8989d2c9d8a4e236e7dd292952347b85
diff --git a/default.xml b/default.xml
index 94620a4..638816a 100644
--- a/default.xml
+++ b/default.xml
@@ -10,9 +10,9 @@
   
   <project name="platform/external/regex-re2" path="external/regex-re2" revision="84e28962b2c2f357b5daccb460501b169193fafe" />
   
-  <project name="platform/external/libcxx" path="external/libcxx" revision="b34f6003c407e0c91d08e5c4aacd07a32d3f03fa" />
-  <project name="platform/external/libcxxabi" path="external/libcxxabi" revision="b3fa2e210e7d170015bebeea5f91be358e87ef33" />
-  <project name="platform/external/libunwind_llvm" path="external/libunwind_llvm" revision="824aaa36e08b25a648562dc8ba0b2797d85a5153" />
+  <project name="platform/external/libcxx" path="external/libcxx" revision="d73f343ced577c0f2f7c0380c01e7b52c7665e29" />
+  <project name="platform/external/libcxxabi" path="external/libcxxabi" revision="2fd58737987874cb4fea1c108abb210bb1d4380e" />
+  <project name="platform/external/libunwind_llvm" path="external/libunwind_llvm" revision="1dc6676dba152ac2a37ebd2610026452c1bda588" />
   <project name="platform/external/llvm" path="external/llvm" revision="0c3d0c5bf04d62953fd1548ceff7d16a08e02953" />
   <project groups="presubmit" name="platform/external/googletest" path="external/googletest" revision="6371bac034f56bcfe3d6a82a8de44b8905a12986" />
   <project groups="presubmit" name="platform/external/python/cpython3" path="external/python/cpython3" revision="b0e85ca1ed410f0196f20f4c37d16dafd4878a3d" />
@@ -23,10 +23,10 @@
   <project groups="presubmit" name="platform/external/vulkan-headers" path="external/vulkan-headers" revision="ffdba7a3a040b32843d8188c9d7c0f2d77311ba4" />
   <project groups="presubmit" name="platform/external/vulkan-tools" path="external/vulkan-tools" revision="75992cfa407810b03676cd144cd3f33c776fd986" />
   <project groups="presubmit" name="platform/external/vulkan-validation-layers" path="external/vulkan-validation-layers" revision="691254d74159549cf5ef8d2a69bb02c062b28a0c" />
-  <project groups="presubmit" name="platform/ndk" path="ndk" revision="27fb6666facf1a1d69489e5c5002ae42f8202bad" />
-  <project name="platform/prebuilts/clang/host/darwin-x86" path="prebuilts/clang/host/darwin-x86" revision="959ad0d53322bfb67a3a481d8939a0e74b2031bd" />
-  <project groups="presubmit" name="platform/prebuilts/clang/host/linux-x86" path="prebuilts/clang/host/linux-x86" revision="5274be15be1049c2e04a7e6a3fab79427eb2e7dd" />
-  <project name="platform/prebuilts/clang/host/windows-x86" path="prebuilts/clang/host/windows-x86" revision="84ec28d02ccb4fe69103098c461955004bddf5a4" />
+  <project groups="presubmit" name="platform/ndk" path="ndk" revision="7e5b7197dc4afd967f9e361ea1b994b9bc5fb6a8" />
+  <project name="platform/prebuilts/clang/host/darwin-x86" path="prebuilts/clang/host/darwin-x86" revision="fb6c691e05952000af217951b40449b88cf33ae8" />
+  <project groups="presubmit" name="platform/prebuilts/clang/host/linux-x86" path="prebuilts/clang/host/linux-x86" revision="a575b3396573e92d5b20ce3ff2431cd6b9eb7529" />
+  <project name="platform/prebuilts/clang/host/windows-x86" path="prebuilts/clang/host/windows-x86" revision="5abd8c2060a827597d0e01fcf2fff8f582887c8d" />
   <project name="platform/prebuilts/cmake/darwin-x86" path="prebuilts/cmake/darwin-x86" revision="f3bfe547014d2d751b7547ad7847a51b0ea34dc8" />
   <project groups="presubmit" name="platform/prebuilts/cmake/linux-x86" path="prebuilts/cmake/linux-x86" revision="da4b9cb08341185e002c8a8c5df73533cdb93b41" />
   <project groups="darwin,arm" name="platform/prebuilts/gcc/darwin-x86/aarch64/aarch64-linux-android-4.9" path="prebuilts/gcc/darwin-x86/aarch64/aarch64-linux-android-4.9" revision="a89c9e0f736c4e3f6b3dc618e248ee4e56419c2a" />
@@ -42,7 +42,7 @@
   <project groups="presubmit" name="platform/prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.17-4.8" path="prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.17-4.8" revision="639243dd5cb2c5ea1313f033c75c8c533813a484" />
   <project groups="presubmit" name="platform/prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8" path="prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8" revision="9c28f035f27080768be11a265aa64fb70924ed90" />
   <project groups="presubmit,linux,x86" name="platform/prebuilts/gcc/linux-x86/x86/x86_64-linux-android-4.9" path="prebuilts/gcc/linux-x86/x86/x86_64-linux-android-4.9" revision="9d8e2e019e5013800ee0adfaffc328f61834ca44" />
-  <project groups="presubmit" name="platform/prebuilts/ndk" path="prebuilts/ndk" revision="63e5451982ba5bf5cd9462d9716c2e38824833db" />
+  <project groups="presubmit" name="platform/prebuilts/ndk" path="prebuilts/ndk" revision="ade9c05fdf040239b85794264a1c8c96635f7e7b" />
   <project name="platform/prebuilts/ninja/darwin-x86" path="prebuilts/ninja/darwin-x86" revision="00f798346dedb4a7a6a6dcc9ad32ff09d66ee0db" />
   <project groups="presubmit" name="platform/prebuilts/ninja/linux-x86" path="prebuilts/ninja/linux-x86" revision="6369b19fc3fbe765636af75d394627e2b92599ed" />
   <project groups="darwin" name="platform/prebuilts/python/darwin-x86/2.7.5" path="prebuilts/python/darwin-x86/2.7.5" revision="0c5958b1636c47ed7c284f859c8e805fd06a0e63" />
@@ -56,7 +56,7 @@
   <project groups="presubmit" name="toolchain/cloog" path="toolchain/cloog" revision="604793eab97d360aef729f064674569ee6dbf3e1" />
   <project groups="presubmit" name="toolchain/expat" path="toolchain/expat" revision="40172a0ae9d40a068f1e1a48ffcf6a1ccf765ed5" />
   <project groups="presubmit" name="toolchain/gcc" path="toolchain/gcc" revision="a9d5e6fb22fe3283eeecfb97211a12c072a7b469" />
-  <project groups="presubmit" name="toolchain/gdb" path="toolchain/gdb" revision="4d64623fc5a88a041fbb0ad5f4ad9d65cb0d4b47" />
+  <project groups="presubmit" name="toolchain/gdb" path="toolchain/gdb" revision="04217dfddb2237b5bcec707f147458e2e3414ba9" />
   <project groups="presubmit" name="toolchain/gmp" path="toolchain/gmp" revision="b2acd5dbf47868ac5b5bc844e16d2cadcbd4c810" />
   <project groups="presubmit" name="toolchain/isl" path="toolchain/isl" revision="0ccf95726af8ce58ad61ff474addbce3a31ba99c" />
   <project groups="presubmit" name="toolchain/make" path="toolchain/make" revision="0e5088b737c763044b8d125b5c018b6e75f0c5a9" />