Merge #17735

17735: examples/gcoap_dtls: Increase stack size r=maribu a=maribu

### Contribution description

As the title says. The stack size was copied over from `tests/pkg_tinydtls_sock_async` cargo-cult style. Also some typos in the README were fixed.

### Testing procedure

Previously on my Nucleo-F767ZI, the CoAP client triggered the MPU stack guard on sending the DTLS hello. With this, the board no longer crashes.

### Issues/PRs references

None

Co-authored-by: Marian Buschsieweke <marian.buschsieweke@ovgu.de>

examples/gcoap_dtls/Makefile

@@ -108,3 +108,4 @@ ifndef CONFIG_KCONFIG_MODULE_GCOAP
 GCOAP_RESEND_BUFS_MAX ?= 2
 CFLAGS += -DCONFIG_GCOAP_RESEND_BUFS_MAX=$(GCOAP_RESEND_BUFS_MAX)
 endif
+CFLAGS += -DTHREAD_STACKSIZE_MAIN=\(2*THREAD_STACKSIZE_LARGE\)

examples/gcoap_dtls/Makefile.ci

@@ -1,28 +1,18 @@
 BOARD_INSUFFICIENT_MEMORY := \
     airfy-beacon \
-    arduino-duemilanove \
-    arduino-leonardo \
-    arduino-mega2560 \
-    arduino-nano \
-    arduino-uno \
-    atmega1284p \
-    atmega328p \
-    atmega328p-xplained-mini \
-    atxmega-a3bu-xplained \
+    b-l072z-lrwan1 \
     blackpill-stm32f103c8 \
-    bluepill-stm32f103c8 \
+    blackpill-stm32f103cb \
     bluepill-stm32f030c8 \
+    bluepill-stm32f103c8 \
+    bluepill-stm32f103cb \
     calliope-mini \
-    derfmega128 \
     hifive1 \
     hifive1b \
     i-nucleo-lrwan1 \
     im880b \
-    mega-xplained \
+    lsn50 \
     microbit \
-    microduino-corerf \
-    msb-430 \
-    msb-430h \
     nrf51dongle \
     nrf6310 \
     nucleo-f030r8 \
@@ -47,9 +37,5 @@ BOARD_INSUFFICIENT_MEMORY := \
     stm32g0316-disco \
     stm32l0538-disco \
     stm32mp157c-dk2 \
-    telosb \
-    waspmote-pro \
     yunjia-nrf51822 \
-    z1 \
-    zigduino \
     #

examples/gcoap_dtls/README.md

@@ -2,13 +2,13 @@
 
 This is an additional gcoap example, but with enabled DTLS. It only provides a
 custom configured makefile, while the code is a symlink to the original gcoap
-example. Therefore, the infos and usage notes of the other README also applies to this
-example.
+example. Therefore, the infos and usage notes of the other README also applies
+to this example.
 
-Please note, that with DTLS the default port is 5684 and not 5683, thus CoAP requests
-must be sent to this port.
+Please note, that with DTLS the default port is 5684 and not 5683, thus CoAP
+requests must be sent to this port.
 
-Since DTLS has higher memory and and ROM requirements, more boards are blacklisted
+Since DTLS has higher memory and ROM requirements, more boards are blacklisted
 for this example compared to the non-DTLS gcoap example.
 
 ### CoAP query with DTLS enabled