cargo install cargo-tarpaulin fails as it is unable to find openssl

[Rahulyamasani]

I see the above error despite openssl11.pc present in the /usr/lib64/pkgconfig/

In an nutshell, the error is that the installation is searching for openssl.pc despite openssl11.pc being present
Installing cargo-tarpaulin v0.25.2
Compiling libc v0.2.141
Compiling proc-macro2 v1.0.56
...
...
Compiling openssl-sys v0.9.85
Compiling libz-sys v1.1.8
error: failed to run custom build command for openssl-sys v0.9.85

Caused by:
process didn't exit successfully: /tmp/cargo-installYt38hp/release/build/openssl-sys-be75c19dfa462b28/build-script-main (exit status: 101)
--- stdout
cargo:rerun-if-env-changed=X86_64_UNKNOWN_LINUX_GNU_OPENSSL_LIB_DIR
X86_64_UNKNOWN_LINUX_GNU_OPENSSL_LIB_DIR unset
cargo:rerun-if-env-changed=OPENSSL_LIB_DIR
OPENSSL_LIB_DIR unset
cargo:rerun-if-env-changed=X86_64_UNKNOWN_LINUX_GNU_OPENSSL_INCLUDE_DIR
X86_64_UNKNOWN_LINUX_GNU_OPENSSL_INCLUDE_DIR unset
cargo:rerun-if-env-changed=OPENSSL_INCLUDE_DIR
OPENSSL_INCLUDE_DIR unset
cargo:rerun-if-env-changed=X86_64_UNKNOWN_LINUX_GNU_OPENSSL_DIR
X86_64_UNKNOWN_LINUX_GNU_OPENSSL_DIR unset
cargo:rerun-if-env-changed=OPENSSL_DIR
OPENSSL_DIR unset
cargo:rerun-if-env-changed=OPENSSL_NO_PKG_CONFIG
cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG
cargo:rerun-if-env-changed=PKG_CONFIG
cargo:rerun-if-env-changed=OPENSSL_STATIC
cargo:rerun-if-env-changed=OPENSSL_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC
cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_PATH
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu
cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR
run pkg_config fail: PKG_CONFIG_ALLOW_SYSTEM_CFLAGS="1" PKG_CONFIG_PATH="/usr/lib64/pkgconfig" "pkg-config" "--libs" "--cflags" "openssl" did not exit successfully: exit status: 1
error: could not find system library 'openssl' required by the 'openssl-sys' crate

--- stderr
Package openssl was not found in the pkg-config search path.
Perhaps you should add the directory containing `openssl.pc'
to the PKG_CONFIG_PATH environment variable
No package 'openssl' found

--- stderr
thread 'main' panicked at '

Could not find directory of OpenSSL installation, and this -sys crate cannot
proceed without this knowledge. If OpenSSL is installed and this crate had
trouble finding it, you can set the OPENSSL_DIR environment variable for the
compilation process.

Make sure you also have the development packages of openssl installed.
For example, libssl-dev on Ubuntu or openssl-devel on Fedora.

If you're in a situation where you think the directory should be found
automatically, please open a bug at https://github.com/sfackler/rust-openssl
and include information about your system as well as this message.

$HOST = x86_64-unknown-linux-gnu
$TARGET = x86_64-unknown-linux-gnu
openssl-sys = 0.9.85

error: failed to compile cargo-tarpaulin v0.25.2, intermediate artifacts can be found at /tmp/cargo-installYt38hp

[xd009642]

If you're in a situation where you think the directory should be found
automatically, please open a bug at sfackler/rust-openssl
and include information about your system as well as this message.

So this is an error in rust-openssl not tarpaulin, so it'll be better to file an issue there. However, tarpaulin does have a vendored-openssl feature which may solve the issue by finding openssl in a different way