CMake: add HTTP/3 support (ngtcp2+nghttp3, quiche)

Add three new CMake Find modules (using the curl license, but I grant
others the right to apply the CMake BSD license instead).

This CMake config is simpler than the autotools one because it assumes
ngtcp2 and nghttp3 to be used together. Another difference is that this
CMake config checks whether QUIC is actually supported by the TLS
library (patched OpenSSL or boringssl) since this can be a common
configuration mistake that could result in build errors later.

Unlike autotools, CMake does not warn you that the features are
experimental. The user is supposed to already know that and read the
documentation. It requires a very special build environment anyway.

Tested with ngtcp2+OpenSSL+nghttp3 and quiche+boringssl, both built from
current git master. Use `LD_DEBUG=files src/curl |& grep need` to figure
out which features (libldap-2.4, libssh2) to disable due to conflicts
with boringssl.

Closes #5359

3 files changed, 257 insertions, 0 deletions

diff --git a/CMake/FindNGHTTP3.cmake b/CMake/FindNGHTTP3.cmake
new file mode 100644
index 000000000..73ce9e188
--- /dev/null
+++ b/CMake/FindNGHTTP3.cmake
@@ -0,0 +1,76 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
+
+#[=======================================================================[.rst:
+FindNGHTTP3
+----------
+
+Find the nghttp3 library
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+``NGHTTP3_FOUND``
+  System has nghttp3
+``NGHTTP3_INCLUDE_DIRS``
+  The nghttp3 include directories.
+``NGHTTP3_LIBRARIES``
+  The libraries needed to use nghttp3
+``NGHTTP3_VERSION``
+  version of nghttp3.
+#]=======================================================================]
+
+if(UNIX)
+  find_package(PkgConfig QUIET)
+  pkg_search_module(PC_NGHTTP3 libnghttp3)
+endif()
+
+find_path(NGHTTP3_INCLUDE_DIR nghttp3/nghttp3.h
+  HINTS
+    ${PC_NGHTTP3_INCLUDEDIR}
+    ${PC_NGHTTP3_INCLUDE_DIRS}
+)
+
+find_library(NGHTTP3_LIBRARY NAMES nghttp3
+  HINTS
+    ${PC_NGHTTP3_LIBDIR}
+    ${PC_NGHTTP3_LIBRARY_DIRS}
+)
+
+if(PC_NGHTTP3_VERSION)
+  set(NGHTTP3_VERSION ${PC_NGHTTP3_VERSION})
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(NGHTTP3
+  REQUIRED_VARS
+    NGHTTP3_LIBRARY
+    NGHTTP3_INCLUDE_DIR
+  VERSION_VAR NGHTTP3_VERSION
+)
+
+if(NGHTTP3_FOUND)
+  set(NGHTTP3_LIBRARIES    ${NGHTTP3_LIBRARY})
+  set(NGHTTP3_INCLUDE_DIRS ${NGHTTP3_INCLUDE_DIR})
+endif()
+
+mark_as_advanced(NGHTTP3_INCLUDE_DIRS NGHTTP3_LIBRARIES)
diff --git a/CMake/FindNGTCP2.cmake b/CMake/FindNGTCP2.cmake
new file mode 100644
index 000000000..a1ed8cd4b
--- /dev/null
+++ b/CMake/FindNGTCP2.cmake
@@ -0,0 +1,113 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
+
+#[=======================================================================[.rst:
+FindNGTCP2
+----------
+
+Find the ngtcp2 library
+
+This module accepts optional COMPONENTS to control the crypto library (these are
+mutually exclusive)::
+
+  OpenSSL:  Use libngtcp2_crypto_openssl
+  GnuTLS:   Use libngtcp2_crypto_gnutls
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+``NGTCP2_FOUND``
+  System has ngtcp2
+``NGTCP2_INCLUDE_DIRS``
+  The ngtcp2 include directories.
+``NGTCP2_LIBRARIES``
+  The libraries needed to use ngtcp2
+``NGTCP2_VERSION``
+  version of ngtcp2.
+#]=======================================================================]
+
+if(UNIX)
+  find_package(PkgConfig QUIET)
+  pkg_search_module(PC_NGTCP2 libngtcp2)
+endif()
+
+find_path(NGTCP2_INCLUDE_DIR ngtcp2/ngtcp2.h
+  HINTS
+    ${PC_NGTCP2_INCLUDEDIR}
+    ${PC_NGTCP2_INCLUDE_DIRS}
+)
+
+find_library(NGTCP2_LIBRARY NAMES ngtcp2
+  HINTS
+    ${PC_NGTCP2_LIBDIR}
+    ${PC_NGTCP2_LIBRARY_DIRS}
+)
+
+if(PC_NGTCP2_VERSION)
+  set(NGTCP2_VERSION ${PC_NGTCP2_VERSION})
+endif()
+
+if(NGTCP2_FIND_COMPONENTS)
+  set(NGTCP2_CRYPTO_BACKEND "")
+  foreach(component IN LISTS NGTCP2_FIND_COMPONENTS)
+    if(component MATCHES "^(OpenSSL|GnuTLS)")
+      if(NGTCP2_CRYPTO_BACKEND)
+        message(FATAL_ERROR "NGTCP2: Only one crypto library can be selected")
+      endif()
+      set(NGTCP2_CRYPTO_BACKEND ${component})
+    endif()
+  endforeach()
+
+  if(NGTCP2_CRYPTO_BACKEND)
+    string(TOLOWER "ngtcp2_crypto_${NGTCP2_CRYPTO_BACKEND}" _crypto_library)
+    if(UNIX)
+      pkg_search_module(PC_${_crypto_library} lib${_crypto_library})
+    endif()
+    find_library(${_crypto_library}_LIBRARY
+      NAMES
+        ${_crypto_library}
+      HINTS
+        ${PC_${_crypto_library}_LIBDIR}
+        ${PC_${_crypto_library}_LIBRARY_DIRS}
+    )
+    if(${_crypto_library}_LIBRARY)
+      set(NGTCP2_${NGTCP2_CRYPTO_BACKEND}_FOUND TRUE)
+      set(NGTCP2_CRYPTO_LIBRARY ${${_crypto_library}_LIBRARY})
+    endif()
+  endif()
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(NGTCP2
+  REQUIRED_VARS
+    NGTCP2_LIBRARY
+    NGTCP2_INCLUDE_DIR
+  VERSION_VAR NGTCP2_VERSION
+  HANDLE_COMPONENTS
+)
+
+if(NGTCP2_FOUND)
+  set(NGTCP2_LIBRARIES    ${NGTCP2_LIBRARY} ${NGTCP2_CRYPTO_LIBRARY})
+  set(NGTCP2_INCLUDE_DIRS ${NGTCP2_INCLUDE_DIR})
+endif()
+
+mark_as_advanced(NGTCP2_INCLUDE_DIRS NGTCP2_LIBRARIES)
diff --git a/CMake/FindQUICHE.cmake b/CMake/FindQUICHE.cmake
new file mode 100644
index 000000000..01d17582b
--- /dev/null
+++ b/CMake/FindQUICHE.cmake
@@ -0,0 +1,68 @@
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.haxx.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+###########################################################################
+
+#[=======================================================================[.rst:
+FindQUICHE
+----------
+
+Find the quiche library
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+``QUICHE_FOUND``
+  System has quiche
+``QUICHE_INCLUDE_DIRS``
+  The quiche include directories.
+``QUICHE_LIBRARIES``
+  The libraries needed to use quiche
+#]=======================================================================]
+if(UNIX)
+  find_package(PkgConfig QUIET)
+  pkg_search_module(PC_QUICHE quiche)
+endif()
+
+find_path(QUICHE_INCLUDE_DIR quiche.h
+  HINTS
+    ${PC_QUICHE_INCLUDEDIR}
+    ${PC_QUICHE_INCLUDE_DIRS}
+)
+
+find_library(QUICHE_LIBRARY NAMES quiche
+  HINTS
+    ${PC_QUICHE_LIBDIR}
+    ${PC_QUICHE_LIBRARY_DIRS}
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(QUICHE
+  REQUIRED_VARS
+    QUICHE_LIBRARY
+    QUICHE_INCLUDE_DIR
+)
+
+if(QUICHE_FOUND)
+  set(QUICHE_LIBRARIES    ${QUICHE_LIBRARY})
+  set(QUICHE_INCLUDE_DIRS ${QUICHE_INCLUDE_DIR})
+endif()
+
+mark_as_advanced(QUICHE_INCLUDE_DIRS QUICHE_LIBRARIES)