bpo-33926: enable GDB tests on Travis CI (GH-14395)

bpo-33926: enable GDB tests on Travis CI (GH-14395) · python/cpython@667eaff

Original file line number	Diff line number	Diff line change
`@@ -14,8 +14,7 @@ env:`
`14`	`14`	`- OPENSSL=1.1.1c`
`15`	`15`	`- OPENSSL_DIR="$HOME/multissl/openssl/${OPENSSL}"`
`16`	`16`	`- PATH="${OPENSSL_DIR}/bin:$PATH"`
`17`		`-# Use -O3 because we don't use debugger on Travis-CI`
`18`		`- - CFLAGS="-I${OPENSSL_DIR}/include -O3"`
	`17`	`+ - CFLAGS="-I${OPENSSL_DIR}/include"`
`19`	`18`	`- LDFLAGS="-L${OPENSSL_DIR}/lib"`
`20`	`19`	`# Set rpath with env var instead of -Wl,-rpath linker flag`
`21`	`20`	`# OpenSSL ignores LDFLAGS when linking bin/openssl`
`@@ -43,6 +42,7 @@ matrix:`
`43`	`42`	`addons:`
`44`	`43`	`apt:`
`45`	`44`	`packages:`
	`45`	`+ - gdb`
`46`	`46`	`- xvfb`
`47`	`47`	`- name: "Documentation build"`
`48`	`48`	`os: linux`