Export of internal Abseil changes

--
642ab296a2c9629c44f3f2ce6911cd2488bcf416 by Derek Mauro <dmauro@google.com>:

Remove an obsolete check in CMakeLists.txt

PiperOrigin-RevId: 352852564

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ce78cb96bcfd162737dbcf35005da3d1d6a3486b by Abseil Team <absl-team@google.com>:

Clarify that the calling *thread* must have locked the mutex in order to unlock
it.

PiperOrigin-RevId: 352801804

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24e1f5f72756046f5265abf618e951c341f09b8d by Derek Mauro <dmauro@google.com>:

Fixes failing CMake string comparisons
https://cmake.org/cmake/help/latest/policy/CMP0054.html

Fixes #791

PiperOrigin-RevId: 352791054

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0ac10bc3f4dca2c4c4b51d7b8196a2eaee9537a1 by Abseil Team <absl-team@google.com>:

Introduce CordRepRing class

This change introduces the CordRepRing class that implements all the lower level / internal implementation for upcoming CordRepRing ring buffer support in cord.

PiperOrigin-RevId: 352771994

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4bd36dda61760785844f0f29f26d90cc18046f75 by Abseil Team <absl-team@google.com>:

Optimize InlineData representation for cord sampling (cordz)

This CL changes InlineData to allow us to store a (future) Cordz Info pointer directly into the inline representation:

- make InlineData a class that provides a public API to set the active union members (tree or chars) and safely access that data.
- change 'tree' and 'profiled' bits to be the 2 least significant bits, allowing us 62 continquous bits for storing a Cordz Info pointer.

PiperOrigin-RevId: 352642411

--
dc55ba71bbce0e6a83e05a453990c51ac3d68426 by Mark Barolak <mbar@google.com>:

Add unit test coverage for the mutating overload of absl::AsciiStrToLower.

PiperOrigin-RevId: 352626006
GitOrigin-RevId: 642ab296a2c9629c44f3f2ce6911cd2488bcf416
Change-Id: I6c5929dd830d3c630e14e7fd5387fc3e25a69100

2 files changed, 7 insertions, 5 deletions

diff --git a/CMake/AbseilDll.cmake b/CMake/AbseilDll.cmake
index 7c98b21a..ac2f325c 100644
--- a/CMake/AbseilDll.cmake
+++ b/CMake/AbseilDll.cmake
@@ -196,6 +196,8 @@ set(ABSL_INTERNAL_DLL_FILES
   "strings/internal/cord_internal.cc"
   "strings/internal/cord_internal.h"
   "strings/internal/cord_rep_flat.h"
+  "strings/internal/cord_rep_ring.cc"
+  "strings/internal/cord_rep_ring.h"
   "strings/internal/charconv_bigint.cc"
   "strings/internal/charconv_bigint.h"
   "strings/internal/charconv_parse.cc"
diff --git a/CMake/AbseilHelpers.cmake b/CMake/AbseilHelpers.cmake
index e88507de..588d4fa2 100644
--- a/CMake/AbseilHelpers.cmake
+++ b/CMake/AbseilHelpers.cmake
@@ -104,7 +104,7 @@ function(absl_cc_library)
     endif()
   endforeach()
 
-  if("${ABSL_CC_SRCS}" STREQUAL "")
+  if(ABSL_CC_SRCS STREQUAL "")
     set(ABSL_CC_LIB_IS_INTERFACE 1)
   else()
     set(ABSL_CC_LIB_IS_INTERFACE 0)
@@ -142,7 +142,7 @@ function(absl_cc_library)
   endif()
 
   # Generate a pkg-config file for every library:
-  if(${_build_type} STREQUAL "static" OR ${_build_type} STREQUAL "shared")
+  if(_build_type STREQUAL "static" OR _build_type STREQUAL "shared")
     if(NOT ABSL_CC_LIB_TESTONLY)
       if(absl_VERSION)
         set(PC_VERSION "${absl_VERSION}")
@@ -183,7 +183,7 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n")
   endif()
 
   if(NOT ABSL_CC_LIB_IS_INTERFACE)
-    if(${_build_type} STREQUAL "dll_dep")
+    if(_build_type STREQUAL "dll_dep")
       # This target depends on the DLL. When adding dependencies to this target,
       # any depended-on-target which is contained inside the DLL is replaced
       # with a dependency on the DLL.
@@ -212,7 +212,7 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n")
           "${_gtest_link_define}"
       )
 
-    elseif(${_build_type} STREQUAL "static" OR ${_build_type} STREQUAL "shared")
+    elseif(_build_type STREQUAL "static" OR _build_type STREQUAL "shared")
       add_library(${_NAME} "")
       target_sources(${_NAME} PRIVATE ${ABSL_CC_LIB_SRCS} ${ABSL_CC_LIB_HDRS})
       target_link_libraries(${_NAME}
@@ -273,7 +273,7 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n")
         $<INSTALL_INTERFACE:${ABSL_INSTALL_INCLUDEDIR}>
       )
 
-    if (${_build_type} STREQUAL "dll")
+    if (_build_type STREQUAL "dll")
         set(ABSL_CC_LIB_DEPS abseil_dll)
     endif()