Merge remote-tracking branch 'origin/pr/2648' into mbedtls-2.16

* origin/pr/2648:
  list-symbols.sh: if the build fails, print the build transcript
  Document "check-names.sh -v"
  all.sh: invoke check-names.sh in print-trace-on-exit mode
  Print a command trace if the check-names.sh exits unexpectedly
diff --git a/.gitignore b/.gitignore
index f40064d..789f57e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,8 +1,20 @@
+# Random seed file created by test scripts and sample programs
+seedfile
+
+# CMake build artifacts:
 CMakeCache.txt
 CMakeFiles
 CTestTestfile.cmake
 cmake_install.cmake
 Testing
+# CMake generates *.dir/ folders for in-tree builds (used by MSVC projects), ignore all of those:
+*.dir/
+# MSVC files generated by CMake:
+/*.sln
+/*.vcxproj
+/*.filters
+
+# Test coverage build artifacts:
 Coverage
 *.gcno
 *.gcda
@@ -10,11 +22,6 @@
 # generated by scripts/memory.sh
 massif-*
 
-# MSVC files generated by CMake:
-/*.sln
-/*.vcxproj
-/*.filters
-
 # MSVC build artifacts:
 *.exe
 *.pdb
@@ -24,5 +31,13 @@
 # Python build artifacts:
 *.pyc
 
-# CMake generates *.dir/ folders for in-tree builds (used by MSVC projects), ignore all of those:
-*.dir/
+# Generated documentation:
+/apidoc
+
+# Editor navigation files:
+/GPATH
+/GRTAGS
+/GSYMS
+/GTAGS
+/TAGS
+/tags
diff --git a/.globalrc b/.globalrc
new file mode 100644
index 0000000..01b2ea5
--- /dev/null
+++ b/.globalrc
@@ -0,0 +1,3 @@
+default:\
+    :langmap=c\:.c.h.function:\
+
diff --git a/ChangeLog b/ChangeLog
index 798e84a..ff44d14 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -46,6 +46,8 @@
      Found by Coverity, reported and fixed by Peter Kolbus (Garmin). Fixes #2309.
    * Add test for minimal value of MBEDTLS_MPI_WINDOW_SIZE to all.sh.
      Contributed by Peter Kolbus (Garmin).
+   * Change wording in the `mbedtls_ssl_conf_max_frag_len()`'s documentation to
+     improve clarity. Fixes #2258.
 
 = mbed TLS 2.16.1 branch released 2019-03-19
 
diff --git a/Makefile b/Makefile
index f4c0a00..1ae6bd9 100644
--- a/Makefile
+++ b/Makefile
@@ -120,3 +120,12 @@
 apidoc_clean:
 	rm -rf apidoc
 endif
+
+## Editor navigation files
+C_SOURCE_FILES = $(wildcard include/*/*.h library/*.[hc] programs/*/*.[hc] tests/suites/*.function)
+tags: $(C_SOURCE_FILES)
+	ctags -o $@ $(C_SOURCE_FILES)
+TAGS: $(C_SOURCE_FILES)
+	etags -o $@ $(C_SOURCE_FILES)
+GPATH GRTAGS GSYMS GTAGS: $(C_SOURCE_FILES)
+	ls $(C_SOURCE_FILES) | gtags -f - --gtagsconf .globalrc
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 8106bb4..d31f6cd 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -2532,22 +2532,28 @@
 
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 /**
- * \brief          Set the maximum fragment length to emit and/or negotiate
- *                 (Default: the smaller of MBEDTLS_SSL_IN_CONTENT_LEN and
- *                 MBEDTLS_SSL_OUT_CONTENT_LEN, usually 2^14 bytes)
+ * \brief          Set the maximum fragment length to emit and/or negotiate.
+ *                 (Typical: the smaller of #MBEDTLS_SSL_IN_CONTENT_LEN and
+ *                 #MBEDTLS_SSL_OUT_CONTENT_LEN, usually `2^14` bytes)
  *                 (Server: set maximum fragment length to emit,
- *                 usually negotiated by the client during handshake
+ *                 usually negotiated by the client during handshake)
  *                 (Client: set maximum fragment length to emit *and*
  *                 negotiate with the server during handshake)
+ *                 (Default: #MBEDTLS_SSL_MAX_FRAG_LEN_NONE)
  *
- * \note           With TLS, this currently only affects ApplicationData (sent
- *                 with \c mbedtls_ssl_read()), not handshake messages.
- *                 With DTLS, this affects both ApplicationData and handshake.
+ * \note           On the client side, the maximum fragment length extension
+ *                 *will not* be used, unless the maximum fragment length has
+ *                 been set via this function to a value different than
+ *                 #MBEDTLS_SSL_MAX_FRAG_LEN_NONE.
  *
  * \note           This sets the maximum length for a record's payload,
  *                 excluding record overhead that will be added to it, see
  *                 \c mbedtls_ssl_get_record_expansion().
  *
+ * \note           With TLS, this currently only affects ApplicationData (sent
+ *                 with \c mbedtls_ssl_read()), not handshake messages.
+ *                 With DTLS, this affects both ApplicationData and handshake.
+ *
  * \note           For DTLS, it is also possible to set a limit for the total
  *                 size of daragrams passed to the transport layer, including
  *                 record overhead, see \c mbedtls_ssl_set_mtu().
diff --git a/scripts/abi_check.py b/scripts/abi_check.py
index f837f7a..30c3fe5 100755
--- a/scripts/abi_check.py
+++ b/scripts/abi_check.py
@@ -148,7 +148,8 @@
         my_environment = os.environ.copy()
         my_environment["CFLAGS"] = "-g -Og"
         my_environment["SHARED"] = "1"
-        my_environment["USE_CRYPTO_SUBMODULE"] = "1"
+        if os.path.exists(os.path.join(git_worktree_path, "crypto")):
+            my_environment["USE_CRYPTO_SUBMODULE"] = "1"
         make_output = subprocess.check_output(
             [self.make_command, "lib"],
             env=my_environment,